Magnetic alignment systems with proximity detection for electronic devices

ABSTRACT

A magnetic alignment system can include a primary annular magnetic alignment component and a secondary annular magnetic alignment component. The primary alignment component can include an inner annular region having a first magnetic orientation, an outer annular region having a second magnetic orientation opposite to the first magnetic orientation, and a non-magnetized central annular region disposed between the primary inner annular region and the primary outer annular region. The secondary alignment component can have a magnetic orientation with a radial component. Additional features, such as a rotational magnetic alignment component and/or an NFC coil and circuitry can be included.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/907,332, filed Sep. 27, 2019, and of U.S. Provisional Application No.63/061,752, filed Aug. 5, 2020. The disclosures of both provisionalapplications are incorporated by reference herein for all purposes.

The following five U.S. patent applications, filed on the same day asthis application, also claim the benefit of the above-referencedprovisional applications: U.S. application Ser. No. 17/028,231, titled“Magnetic Alignment Systems for Electronic Devices”; U.S. applicationSer. No. 17/028,275, titled “Magnetic Alignment Systems with RotationalAlignment Component for Electronic Devices”; U.S. application Ser. No.17/028,256, titled “Magnetic Alignment Systems with NFC for ElectronicDevices”; U.S. application Ser. No. 17/028,310, titled “WirelessCharging Modules with Magnetic Alignment Components”; and U.S.application Ser. No. 17/028,325, titled “Accessory Insert Modules withMagnetic Alignment Components.”

BACKGROUND

The present disclosure relates generally to consumer electronic devicesand more particularly to magnetic alignment components and systems thatfacilitate establishing and maintaining a desired alignment between two(or more) devices, e.g., for purposes of enabling efficient wirelesspower transfer between the devices.

Portable electronic devices (e.g., mobile phones, media players,electronic watches, and the like) operate when there is charge stored intheir batteries. Some portable electronic devices include a rechargeablebattery that can be recharged by coupling the portable electronic deviceto a power source through a physical connection, such as through acharging cord. Using a charging cord to charge a battery in a portableelectronic device, however, requires the portable electronic device tobe physically tethered to a power outlet. Additionally, using a chargingcord requires the mobile device to have a connector, typically areceptacle connector, configured to mate with a connector, typically aplug connector, of the charging cord. The receptacle connector includesa cavity in the portable electronic device that provides an avenue viawhich dust and moisture can intrude and damage the device. Further, auser of the portable electronic device has to physically connect thecharging cable to the receptacle connector in order to charge thebattery.

To avoid such shortcomings, wireless charging technologies have beendeveloped that exploit electromagnetic induction to charge portableelectronic devices without the need for a charging cord. For example,some portable electronic devices can be recharged by merely resting thedevice on a charging surface of a wireless charger device. A transmittercoil disposed below the charging surface is driven with an alternatingcurrent that produces a time-varying magnetic flux that induces acurrent in a corresponding receiver coil in the portable electronicdevice. The induced current can be used by the portable electronicdevice to charge its internal battery. Some portable electronic deviceshave been designed to not only receive power wirelessly but also totransmit power wirelessly to other portable electronic devices, such asaccessory devices.

SUMMARY

Among other factors, the efficiency of wireless power transfer dependson the alignment between the transmitter and receiver coils. Forinstance, a transmitter coil and receiver coil may perform best whenthey are aligned coaxially. Where a portable electronic device has aflat surface with no guiding features, finding the proper alignment canbe difficult. Often, alignment is achieved by trial and error, with theuser shifting the relative positions of the device and charger andobserving the effect on charging performance. Establishing optimalalignment in this manner can be time-consuming. Further, the absence ofsurface features can make it difficult to maintain optimal alignment.For example, if the portable electronic device and/or charger arejostled during charging, they may be shifted out of alignment. For theseand other reasons, improved techniques for establishing and maintainingalignment between electronic devices would be desirable.

According to embodiments described herein, a portable electronic deviceand an accessory device can include complementary magnetic alignmentcomponents that facilitate alignment of the accessory device with theportable electronic device and/or attachment of the accessory device tothe portable electronic device. The magnetic alignment components caninclude annular magnetic alignment components that, in some embodiments,can surround inductive charging transmitter and receiver coils. In thenomenclature used herein, a “primary” annular magnetic alignmentcomponent refers to an annular magnetic alignment component used in awireless charger device or other terminal accessory. A “secondary”annular magnetic alignment component refers to an annular magneticalignment component used in a portable electronic device. An “auxiliary”annular magnetic alignment component refers to an annular magneticalignment component used in a charge-through accessory.

In some embodiments, a magnetic alignment system can also include arotational magnetic alignment component that facilitates aligning twodevices in a preferred rotational orientation. A rotational magneticalignment component can include, for example, one or more magnetsdisposed outboard of an annular alignment component. It should beunderstood that any device that has an annular alignment component mightor might not also have a rotational alignment component, and rotationalalignment components may be categorized as primary, secondary, orauxiliary depending on the type of device.

In some embodiments, magnetic alignment components can be fixed inposition within a device housing. Alternatively, any or all of themagnetic alignment components in a device (including annular and/orrotational alignment components) can be made movable in the axial and/orlateral direction. A movable magnetic alignment component can allow themagnets to be moved (e.g., axially) into closer proximity to increasemagnetic forces holding the devices in alignment or moved away from eachother to reduce the magnetic forces holding the devices in alignment.

In some embodiments, a magnetic alignment system can also include anear-field communication (NFC) coil and supporting circuitry to allowdevices to identify themselves to each other using an NFC protocol. AnNFC coil in a particular device can be an annular coil that is disposedinboard of the annular alignment component or outboard of the annularalignment component. For example, in a device that has an annularalignment component surrounding an inductive charging coil, the NFC coilcan be disposed in an annular gap between the inductive charging coiland the annular alignment component. It should be understood that an NFCcomponent is optional in the context of providing magnetic alignment andcan be used with moving or fixed magnetic alignment components.

The following detailed description, together with the accompanyingdrawings, will provide a better understanding of the nature andadvantages of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a simplified representation of a wireless charging systemincorporating a magnetic alignment system according to some embodiments.

FIG. 2A shows a perspective view of a magnetic alignment systemaccording to some embodiments, and FIG. 2B shows a cross-section throughthe magnetic alignment system of FIG. 2A.

FIG. 3A shows a perspective view of a magnetic alignment systemaccording to some embodiments, and FIG. 3B shows a cross-section throughthe magnetic alignment system of FIG. 3A.

FIG. 4 shows a simplified top-down view of a secondary alignmentcomponent according to some embodiments.

FIG. 5A shows a perspective view of a magnetic alignment systemaccording to some embodiments, and FIG. 5B shows an axial cross-sectionview through a portion of the system of FIG. 5A.

FIGS. 5C-5E show examples of arcuate magnets with radial magneticorientation according to some embodiments.

FIGS. 6A and 6B show graphs of force profiles for different magneticalignment systems, according to some embodiments.

FIG. 7 shows a simplified top-down view of a secondary alignmentcomponent according to some embodiments.

FIG. 8A shows a perspective view of a magnetic alignment systemaccording to some embodiments, and FIGS. 8B and 8C show axialcross-section views through different portions of the system of FIG. 8A.

FIGS. 9A and 9B show simplified top-down views of secondary alignmentcomponents according to various embodiments.

FIG. 10 shows a simplified top-down view of a secondary alignmentcomponent according to some embodiments.

FIG. 11 illustrates an example of an annular alignment component havinga gap according to some embodiments.

FIGS. 12A and 12B show examples portable electronic devicesincorporating a magnetic alignment component according to someembodiments.

FIG. 13 shows a simplified view of a wireless charger deviceincorporating a magnetic alignment component according to someembodiments.

FIG. 14A shows a simplified perspective view of a system including aportable electronic device in alignment with a wireless charger deviceaccording to some embodiments, and FIG. 14B shows a simplified partialcross section view of the system of FIG. 14A.

FIG. 15 is a block diagram illustrating an exemplary wireless chargingsystem including devices that can be aligned together via a magneticalignment system according to some embodiments.

FIG. 16 shows an example of a portable electronic device and anaccessory incorporating a magnetic alignment system with an annularalignment component and a rotational alignment component according tosome embodiments.

FIGS. 17A and 17B show an example of rotational alignment according tosome embodiments.

FIGS. 18A and 18B show a perspective view and a top view of a rotationalalignment component having a “z-pole” configuration according to someembodiments.

FIGS. 19A and 19B show a perspective view and a top view of a rotationalalignment component having a “quad-pole” configuration according to someembodiments.

FIGS. 20A and 20B show a perspective view and a top view of a rotationalalignment component having an “annulus design” configuration accordingto some embodiments.

FIGS. 21A and 21B show a perspective view and a top view of a rotationalalignment component having a “triple pole” configuration according tosome embodiments.

FIG. 22 shows graphs of torque as a function of angular rotation formagnetic alignment systems having rotational alignment componentsaccording to various embodiments.

FIG. 23 shows a portable electronic device having an alignment systemwith multiple rotational alignment components according to someembodiments.

FIG. 24 shows a simplified representation of a wireless charging systemincorporating a magnetic alignment system according to some embodiments.

FIG. 25A shows a perspective view of a magnetic alignment systemaccording to some embodiments, and FIG. 25B shows a cross-sectionthrough the magnetic alignment system of FIG. 25A.

FIG. 26A shows a perspective view of a magnetic alignment systemaccording to some embodiments, and FIG. 26B shows a cross-sectionthrough the magnetic alignment system of FIG. 26A.

FIG. 27 shows a simplified rear view of an accessory deviceincorporating a magnetic alignment component according to someembodiments.

FIG. 28A shows a simplified perspective view of a system including aportable electronic device in alignment with an accessory device and awireless charger device according to some embodiments, and FIG. 28Bshows a simplified partial cross section view of the system of FIG. 28A.

FIG. 29 is a block diagram illustrating an exemplary wireless chargingsystem including devices that can be aligned together via a magneticalignment system according to some embodiments.

FIGS. 30A-30C illustrate moving magnets according to an embodiment ofthe present invention.

FIGS. 31A and 31B illustrate a moving magnetic structure according to anembodiment of the present invention.

FIGS. 32A and 32B illustrate a moving magnetic structure according to anembodiment of the present invention.

FIGS. 33-35 illustrate a moving magnetic structure according to anembodiment of the present invention.

FIG. 36 illustrates a normal force between a first magnet in a firstelectronic device and a second magnet in a second electronic device.

FIG. 37 illustrates a shear force between a first magnet in a firstelectronic device and a second magnet in a second electronic device.

FIGS. 38A and 38B illustrate a moving magnet in conjunction with a highfriction surface according to an embodiment of the present invention.

FIGS. 39A and 39B illustrate a moving magnet in conjunction with a highfriction surface according to an embodiment of the present invention.

FIGS. 40A and 40B illustrate a moving magnet in conjunction with a highfriction surface according to an embodiment of the present invention.

FIGS. 41A and 41B illustrate another moving magnet in conjunction with ahigh friction surface according to an embodiment of the presentinvention.

FIG. 42 illustrates a cutaway side view of another moving magnetstructure according to an embodiment of the present invention.

FIG. 43 is a partially transparent view of the moving magnet structureof FIG. 42.

FIG. 44 is another cutaway side view of the electronic device of FIG.42.

FIGS. 45 and 46 illustrate the electronic device of FIG. 42 as itengages with a second electronic device.

FIGS. 47A and 47B illustrate structures for constraining motions ofmagnets in an electronic device according to an embodiment of thepresent invention.

FIGS. 48A and 48B illustrate structures for constraining motions ofmagnets in an electronic device according to an embodiment of thepresent invention.

FIGS. 49A and 49B illustrate structures for constraining motions ofmagnets an electronic device according to an embodiment of the presentinvention.

FIG. 50 shows a simplified back view of a portable electronic deviceaccording to some embodiments.

FIG. 51 shows an exploded view of a wireless charging and alignmentassembly for a portable electronic device incorporating an NFC readeraccording to some embodiments.

FIG. 52 shows a simplified cross-section view of a portion of theportable electronic device of FIG. 50 incorporating the assembly of FIG.51.

FIG. 53 shows an exploded view of a wireless charger deviceincorporating an NFC tag circuit according to some embodiments.

FIGS. 54A and 54B show partial cross-section views of wireless chargerdevice according to some embodiments.

FIG. 55 shows an example of an accessory device incorporating anauxiliary alignment component with an NFC tag circuit and coil accordingto some embodiments.

FIG. 56 shows a more detailed view of an NFC tag circuit assemblyaccording to some embodiments.

FIG. 57 shows an exploded view of an NFC tag circuit assembly accordingto some embodiments.

FIG. 58 shows a partial cross section view of an accessory according tosome embodiments.

FIG. 59 shows an example of another accessory device according to someembodiments.

FIG. 60 shows an enlarged view of an auxiliary annular magneticalignment component and NFC tag circuit assembly according to someembodiments.

FIG. 61 shows an exploded view of an NFC tag circuit assembly accordingto some embodiments.

FIG. 62 shows a simplified partial cross-section view of a system thatincludes a wireless charger device, a portable electronic device, and anaccessory device according to some embodiments.

FIG. 63 shows an example of an accessory device having an auxiliaryalignment component with an NFC tag circuit and coil according to someembodiments.

FIG. 64 shows a simplified partial cross-section view of a system thatincludes a wireless charger device, a portable electronic device, and anaccessory device according to some embodiments.

FIG. 65 shows a flow diagram of a process that can be implemented in aportable electronic device according to some embodiments.

FIG. 66 shows an exploded view of a wireless charger device according tosome embodiments.

FIG. 67 shows a simplified partial cross-section view of a wirelesscharger device according to some embodiments.

FIG. 68 shows an exploded view of a cable assembly with incorporatedpower circuitry that can be connected to a wireless charger deviceaccording to some embodiments.

FIG. 69A shows an example of a portable electronic device having awireless power module according to some embodiments.

FIG. 69B shows a cross section view of the wireless power module of FIG.69A.

FIG. 70 shows a more detailed top view of a wireless power moduleaccording to some embodiments.

FIGS. 71A-71D show cross section views of NFC coils that can be used ina wireless power module according to various embodiments.

FIG. 72 shows an rear view of a case according to some embodiments.

FIG. 73A shows a simplified axial view of internal components of anannular alignment assembly for a case according to some embodiments.

FIG. 73B shows a cross section view of the annular alignment assembly ofFIG. 73A.

FIG. 73C shows a more detailed view of an NFC tag circuit assemblyaccording to some embodiments.

FIG. 74 shows an exploded view of an annular alignment assembly androtational alignment assembly according to some embodiments.

FIG. 75 shows a cross-section view of a portion of a rear panel of acase according to some embodiments.

FIGS. 76A and 76B show top and bottom perspective views of a chargeralignment module according to some embodiments.

FIG. 77 shows an exploded view of a charger alignment module accordingto some embodiments.

FIG. 78 shows a top perspective view of a teardrop-shaped charger moduleaccording to some embodiments.

FIG. 79A is a front view and FIG. 79B is a top view of an accessoryinsert module according to some embodiments.

FIG. 80 shows an exploded view of an accessory insert module accordingto some embodiments.

FIG. 81 shows an exploded view of an accessory insert module accordingto some embodiments.

FIGS. 82 and 83 show partial cross-section views of accessory insertmodules according to various embodiments.

FIG. 84 is a partial cross section view of an annular accessory insertmodule according to some embodiments.

DETAILED DESCRIPTION

Described herein are various embodiments of magnetic alignment systemsand components thereof. A magnetic alignment system can include annularalignment components, where each annular alignment component cancomprise a ring of magnets (or a single annular magnet) having aparticular magnetic orientation or pattern of magnetic orientations suchthat a “primary” annular alignment component can attract and hold acomplementary “secondary” annular alignment component. Magneticalignment components can be incorporated into a variety of devices, anda magnetic alignment component in one device can attract another devicehaving a complementary magnetic alignment component into a desiredalignment and/or hold the other device in a desired alignment. (Devicesaligned by a magnetic alignment system may be said to be “attached” toeach other.)

For purposes of the present description, a number of differentcategories of devices can be distinguished. As used herein, a “portableelectronic device” refers generally to any electronic device that isportable and that consumes power and provides at least some interactionwith the user. Examples of portable electronic devices include: smartphones and other mobile phones; tablet computers; laptop computers;wearable devices (e.g., smart watches, headphones, earbuds); and anyother electronic device that a user may carry or wear. Other portableelectronic devices can include robotic devices, remote-controlleddevices, personal-care appliances, and so on.

An “accessory device” (or “accessory”) refers generally to a device thatis useful in connection with a portable electronic device to enhance thefunctionality and/or esthetics of the portable electronic device. Manycategories of accessories may incorporate magnetic alignment. Forexample, one category of accessories includes wireless chargeraccessories. As used herein, a “wireless charger accessory” (or“wireless charger device” or just “wireless charger”) is an accessorythat can provide power to a portable electronic device using wirelesspower transfer techniques. A “battery pack” (or “external battery”) is atype of wireless charger accessory that incorporates a battery to storecharge that can be transferred to the portable electronic device. Insome embodiments, a battery pack may also receive power wirelessly fromanother wireless charger accessory. Wireless charger accessories mayalso be referred to as “active” accessories, in reference to theirability to provide and/or receive power. Other accessories are “passiveaccessories” that do not provide or receive power. For example, somepassive accessories are “cases” that can cover one or more surfaces ofthe portable electronic device to provide protection (e.g., againstdamage caused by impact of the portable electronic device with otherobjects), esthetic enhancements (e.g., decorative colors or the like),and/or functional enhancements (e.g., cases that incorporate storagepockets, batteries, card readers, or sensors of various types). Casescan have a variety of form factors. For example, a “tray” can refer to acase that has a rear panel covering the back surface of the portableelectronic device and side surfaces to secure the portable electronicdevice in the tray while leaving the front surface (which may include adisplay) exposed. A “sleeve” can refer to a case that has front and backpanels with an open end (or “throat”) into which a portable electronicdevice can be inserted so that the front and back surfaces of the deviceare covered; in some instances, the front panel of a sleeve can includea window through which a portion (or all) of a display of the portableelectronic device is visible. A “folio” can refer to a case that has aretention portion that covers at least the back surface (and sometimesalso one or more side surfaces) of the portable electronic device and acover that can be closed to cover the display or opened to expose thedisplay. It should be understood that not all cases are passiveaccessories. For example, a “battery case” can incorporate a batterypack in addition to protective and/or esthetic features; a battery casecan be shaped generally as a tray, sleeve, or folio. Other examples ofactive cases can include cases that incorporate card readers, sensors,batteries, or other electronic components that enhance functionality ofa portable electronic device.

In the present description, a distinction is sometimes made between a“charge-through accessory,” which is an accessory that can be positionedbetween a portable electronic device and a wireless charger devicewithout interfering with wireless power transfer between the wirelesscharger device and the portable electronic device, and a “terminalaccessory,” which is an accessory that is not a charge-throughaccessory. A wireless charging accessory is typically a terminalaccessory, but not all terminal accessories provide wireless charging ofa portable electronic device. For example some terminal accessories canbe “mounting” accessories that are designed to hold the portableelectronic device in a particular position. Examples of mounting includetripods, docking stations, other stands, or mounts that can hold aportable electronic device in a desired position and/or orientation(which might or might not be adjustable). Such accessories might ormight not incorporate wireless charging capability.

According to embodiments described herein, a portable electronic deviceand an accessory device can include complementary magnetic alignmentcomponents that facilitate alignment of the accessory device with theportable electronic device and/or attachment of the accessory device tothe portable electronic device. The magnetic alignment components caninclude annular magnetic alignment components that, in some embodiments,can surround inductive charging transmitter and receiver coils. (It willbe apparent that an annular magnetic alignment component can also beused in a device that does not have an inductive charging coil.) In thenomenclature used herein, a “primary” annular magnetic alignmentcomponent refers to an annular magnetic alignment component used in awireless charger device or other terminal accessory. A “secondary”annular magnetic alignment component refers to an annular magneticalignment component used in a portable electronic device. An “auxiliary”annular magnetic alignment component refers to an annular magneticalignment component used in a charge-through accessory. (In thisdisclosure, adjectives such as “annular,” “magnetic,” “primary,”“secondary” and “auxiliary” may be omitted when the context is clear.)The primary and secondary annular alignment components have magneticorientations that are complementary, such that the primary and secondaryannular alignment components can attract each other and attach devicescontaining these components in a desired alignment. For example, aprimary annular alignment component can have a “quad-pole” magneticconfiguration, with an inner annular region having a magnetic polarityin a first axial direction, an outer annular region having a magneticpolarity in a second axial direction opposite the first direction, and acentral non-magnetized region between the inner annular region and theouter annular region. A secondary annular alignment component can have aradial magnetic configuration (e.g., with north pole oriented radiallyinward or radially outward, either exactly or approximately; examplesare described below). When aligned, the primary and secondary annularalignment components can form a closed magnetic loop such that the DCmagnetic flux is largely contained within the magnets. Alternatively, asecondary annular alignment component can also have a quad-pole magneticconfiguration matching that of the primary annular alignment component.An auxiliary annular alignment component can operate as a “repeater” andcan have a quad-pole configuration matching that of the primary annularalignment component.

In some embodiments, a magnetic alignment system can also include arotational magnetic alignment component that facilitates aligning twodevices in a preferred rotational orientation. A rotational magneticalignment component can include, for example, one or more magnetsdisposed outboard of an annular alignment component. The magnet(s) of arotational alignment component can have complementary orientations, suchthe rotational alignment components in two devices can attract eachother and attach the two devices containing these components in adesired rotational orientation. For example, a rotational alignmentcomponent can have a quad-pole configuration with a first magnetizedregion (e.g., extending along one side of a rectangular magnet) having amagnetic polarity in a first axial direction, a second magnetized region(e.g., extending along the opposite side of the rectangular magnet)having a magnetic polarity in a second axial direction opposite thefirst direction, and a central non-magnetized region. As anotherexample, a rotational alignment component can have a triple-poleconfiguration with a first magnetized region (e.g., extending along oneside of a rectangular magnet) having a magnetic polarity in a firstaxial direction, a second magnetized region (e.g., extending along theopposite side of the rectangular magnet) also having a magnetic polaritythe first axial direction, a central magnetized region having a magneticpolarity in a second axial direction opposite the first direction, andnon-magnetized regions between the central magnetized region and each ofthe first and second magnetized regions. Other magnetic configurationscan be substituted. It should be understood that any device that has anannular magnetic alignment component might or might not also have arotational magnetic alignment component, and rotational alignmentcomponents may be categorized as primary, secondary, or auxiliary, e.g.,depending on the type of device.

In some embodiments, magnetic alignment components can be fixed inposition within a device housing. Alternatively, any or all of themagnetic alignment components in a device (including annular and/orrotational alignment components) can be made movable in the axial and/orlateral direction. A movable magnetic alignment component can allow themagnets to be moved (e.g., axially) into closer proximity to increasemagnetic forces holding the devices in alignment or moved away from eachother to reduce the magnetic forces holding the devices in alignment.

In some embodiments, a magnetic alignment system can also include anear-field communication (NFC) coil and supporting circuitry to allowdevices to identify themselves to each other using an NFC protocol. AnNFC coil in a particular device can be an annular coil that is disposedinboard of the annular alignment component or outboard of the annularalignment component. For example, in a device that has an annularalignment component surrounding an inductive charging coil, the NFC coilcan be disposed in an annular gap between the inductive charging coiland the annular alignment component. It should be understood that an NFCcomponent is optional in the context of providing magnetic alignment.

Accordingly, while the following description focuses on specificexamples incorporating various combinations of components, it should beunderstood that any device can have has an annular magnetic alignmentcomponent, which can be, for example, any of the primary, secondary, orauxiliary annular magnetic alignment components described herein.Further, any device that has an annular magnetic alignment component canalso have a rotational magnetic alignment component, which can be, forexample, any of the rotational magnetic alignment components describedherein. Further, any device that has an annular magnetic alignmentcomponent, regardless of whether it also has a rotational magneticalignment component, can also have an NFC coil (and supporting readercircuitry and/or tag circuitry), which can be implemented, e.g.,according to any of the examples described herein.

1. Primary and Secondary Annular Magnetic Alignment Components

1.1. Overview of Magnetic Alignment Systems

FIG. 1 shows a simplified representation of a wireless charging system100 incorporating a magnetic alignment system 106 according to someembodiments. A portable electronic device 104 is positioned on acharging surface 108 of a wireless charger device 102. Portableelectronic device 104 can be a consumer electronic device, such as asmart phone, tablet, wearable device, or the like, or any otherelectronic device for which wireless charging is desired. Wirelesscharger device 102 can be any device that is configured to generatetime-varying magnetic flux to induce a current in a suitably configuredreceiving device. For instance, wireless charger device 102 can be awireless charging mat, puck, docking station, or the like. Wirelesscharger device 102 can include or have access to a power source such asbattery power or standard AC power.

To enable wireless power transfer, portable electronic device 104 andwireless charger device 102 can include inductive coils 110 and 112,respectively, which can operate to transfer power between them. Forexample, inductive coil 112 can be a transmitter coil that generates atime-varying magnetic flux 114, and inductive coil 110 can be a receivercoil in which an electric current is induced in response to time-varyingmagnetic flux 114. The received electric current can be used to charge abattery of portable electronic device 104, to provide operating power toa component of portable electronic device 104, and/or for other purposesas desired. (“Wireless power transfer” and “inductive power transfer,”as used herein, refer generally to the process of generating atime-varying magnetic field in a conductive coil of a first device thatinduces an electric current in a conductive coil of a second device.)

To enable efficient wireless power transfer, it is desirable to aligninductive coils 112 and 110. According to some embodiments, magneticalignment system 106 can provide such alignment. In the example shown inFIG. 1, magnetic alignment system 106 includes a primary magneticalignment component 116 disposed within or on a surface of wirelesscharger device 102 and a secondary magnetic alignment component 118disposed within or on a surface of portable electronic device 102.Primary and secondary alignment components 116 and 118 are configured tomagnetically attract one another into an aligned position in whichinductive coils 110 and 112 are aligned with one another to provideefficient wireless power transfer.

According to embodiments described herein, a magnetic alignmentcomponent (including a primary or secondary alignment component) of amagnetic alignment system can be formed of arcuate magnets arranged inan annular configuration. In some embodiments, each magnet can have itsmagnetic polarity oriented in a desired direction so that magneticattraction between the primary and secondary magnetic alignmentcomponents provides a desired alignment. In some embodiments, an arcuatemagnet can include a first magnetic region with magnetic polarityoriented in a first direction and a second magnetic region with magneticpolarity oriented in a second direction different from (e.g., oppositeto) the first direction. As will be described, different configurationscan provide different degrees of magnetic field leakage.

1.2. Magnetic Alignment Systems with a Single Axial Magnetic Orientation

FIG. 2A shows a perspective view of a magnetic alignment system 200according to some embodiments, and FIG. 2B shows a cross-section throughmagnetic alignment system 200 across the cut plane indicated in FIG. 2A.Magnetic alignment system 200 can be an implementation of magneticalignment system 106 of FIG. 1. In magnetic alignment system 200, thealignment components all have magnetic polarity oriented in the samedirection (along the axis of the annular configuration). For convenienceof description, an “axial” direction (also referred to as a“longitudinal” or “z” direction) is defined to be parallel to an axis ofrotational symmetry 201 of magnetic alignment system 200, and atransverse plane (also referred to as a “lateral” or “x” or “y”direction) is defined to be normal to axis 201. The term “proximal side”or “proximal surface” is used herein to refer to a side or surface ofone alignment component that is oriented toward the other alignmentcomponent when the magnetic alignment system is aligned, and the term“distal side” or “distal surface” is used to refer to a side or surfaceopposite the proximal side or surface. (The terms “top” and “bottom” maybe used in reference to a particular view shown in a drawing but have noother significance.)

As shown in FIG. 2A, magnetic alignment system 200 can include a primaryalignment component 216 (which can be an implementation of primaryalignment component 116 of FIG. 1) and a secondary alignment component218 (which can be an implementation of secondary alignment component 118of FIG. 1). Primary alignment component 216 and secondary alignmentcomponent 218 have annular shapes and may also be referred to as“annular” alignment components. The particular dimensions can be chosenas desired. In some embodiments, primary alignment component 216 andsecondary alignment component 218 can each have an outer diameter ofabout 54 mm and a radial width of about 4 mm. The outer diameters andradial widths of primary alignment component 216 and secondary alignmentcomponent 218 need not be exactly equal. For instance, the radial widthof secondary alignment component 218 can be slightly less than theradial width of primary alignment component 216 and/or the outerdiameter of secondary alignment component 218 can also be slightly lessthan the radial width of primary alignment component 216 so that, whenin alignment, the inner and outer sides of primary alignment component216 extend beyond the corresponding inner and outer sides of secondaryalignment component 218. Thicknesses (or axial dimensions) of primaryalignment component 216 and secondary alignment component 218 can alsobe chosen as desired. In some embodiments, primary alignment component216 has a thickness of about 1.5 mm while secondary alignment component218 has a thickness of about 0.37 mm.

Primary alignment component 216 can include a number of sectors, each ofwhich can be formed of one or more primary arcuate magnets 226, andsecondary alignment component 218 can include a number of sectors, eachof which can be formed of one or more secondary arcuate magnets 228. Inthe example shown, the number of primary magnets 226 is equal to thenumber of secondary magnets 228, and each sector includes exactly onemagnet, but this is not required. Primary magnets 226 and secondarymagnets 228 can have arcuate (or curved) shapes in the transverse planesuch that when primary magnets 226 (or secondary magnets 228) arepositioned adjacent to one another end-to-end, primary magnets 226 (orsecondary magnets 228) form an annular structure as shown. In someembodiments, primary magnets 226 can be in contact with each other atinterfaces 230, and secondary magnets 228 can be in contact with eachother at interfaces 232. Alternatively, small gaps or spaces mayseparate adjacent primary magnets 226 or secondary magnets 228,providing a greater degree of tolerance during manufacturing.

In some embodiments, primary alignment component 216 can also include anannular shield 214 (also referred to as a DC magnetic shield or DCshield) disposed on a distal surface of primary magnets 226. In someembodiments, shield 214 can be formed as a single annular piece ofmaterial and adhered to primary magnets 226 to secure primary magnets226 into position. Shield 214 can be formed of a material that has highmagnetic permeability, such as stainless steel, and can redirectmagnetic fields to prevent them from propagating beyond the distal sideof primary alignment component 216, thereby protecting sensitiveelectronic components located beyond the distal side of primaryalignment component 216 from magnetic interference.

Primary magnets 226 and secondary magnets 228 (and all other magnetsdescribed herein) can be made of a magnetic material such as an NdFeBmaterial, other rare earth magnetic materials, or other materials thatcan be magnetized to create a persistent magnetic field. In someembodiments, the magnets can be plated with a thin layer (e.g., 7-13 μm)of NiCuNi or similar materials. Each primary magnet 226 and eachsecondary magnet 228 can have a monolithic structure having a singlemagnetic region with a magnetic polarity aligned in the axial directionas shown by magnetic polarity indicators 215, 217 in FIG. 2B. Forexample, each primary magnet 226 and each secondary magnet 228 can be abar magnet that has been ground and shaped into an arcuate structurehaving an axial magnetic orientation. (As will be apparent, the term“magnetic orientation” refers to the direction of orientation of themagnetic polarity of a magnet or magnetized region.) In the exampleshown, primary magnet 226 has its north pole oriented toward theproximal surface and south pole oriented toward the distal surface whilesecondary magnet 228 has its south pole oriented toward the proximalsurface and north pole oriented toward the distal surface. In otherembodiments, the magnetic orientations can be reversed such that primarymagnet 226 has its south pole oriented toward the proximal surface andnorth pole oriented toward the distal surface while secondary magnet 228has its north pole oriented toward the proximal surface and south poleoriented toward the distal surface.

As shown in FIG. 2B, the axial magnetic orientation of primary magnet226 and secondary magnet 228 can generate magnetic fields 240 that exertan attractive force between primary magnet 226 and secondary magnet 228,thereby facilitating alignment between respective electronic devices inwhich primary alignment component 216 and secondary alignment component218 are disposed (e.g., as shown in FIG. 1). While shield 214 canredirect some of magnetic fields 240 away from regions below primarymagnet 226, magnetic fields 240 may still propagate to regions laterallyadjacent to primary magnet 226 and secondary magnet 228. In someembodiments, the lateral propagation of magnetic fields 240 may resultin magnetic field leakage to other magnetically sensitive components.For instance, if an inductive coil having a ferromagnetic shield isplaced in the interior (or inboard) region of annular primary alignmentcomponent 216 (or secondary alignment component 218), leakage ofmagnetic fields 240 may saturate the ferrimagnetic shield, which candegrade wireless charging performance.

It will be appreciated that magnetic alignment system 200 isillustrative and that variations and modifications are possible. Forinstance, while primary alignment component 216 and secondary alignmentcomponent 218 are each shown as being constructed of eight arcuatemagnets, other embodiments may use a different number of magnets, suchas sixteen magnets, thirty-six magnets, or any other number of magnets,and the number of primary magnets need not be equal to the number ofsecondary magnets. In other embodiments, primary alignment component 216and/or secondary alignment component 218 can each be formed of a single,monolithic annular magnet; however, segmenting magnetic alignmentcomponents 216 and 218 into arcuate magnets may improve manufacturingbecause (for some types of magnetic material) smaller arcuate segmentsmay be less brittle than a single, monolithic annular magnet and lessprone to yield loss due to physical stresses imposed on the magneticmaterial during manufacturing.

1.3. Magnetic Alignment Systems with Closed-Loop Configurations

As noted above with reference to FIG. 2B, a magnetic alignment systemwith a single axial magnetic orientation may allow lateral leakage ofmagnetic fields, which may adversely affect performance of othercomponents of an electronic device. Accordingly, some embodimentsprovide magnetic alignment systems with a “closed-loop” configurationthat reduces magnetic field leakage. Examples will now be described.

FIG. 3A shows a perspective view of a magnetic alignment system 300according to some embodiments, and FIG. 3B shows a cross-section throughmagnetic alignment system 300 across the cut plane indicated in FIG. 3A.Magnetic alignment system 300 can be an implementation of magneticalignment system 106 of FIG. 1. In magnetic alignment system 300, thealignment components have magnetic components configured in a “closedloop” configuration as described below.

As shown in FIG. 3A, magnetic alignment system 300 can include a primaryalignment component 316 (which can be an implementation of primaryalignment component 116 of FIG. 1) and a secondary alignment component318 (which can be an implementation of secondary alignment component 118of FIG. 1). Primary alignment component 316 and secondary alignmentcomponent 318 have annular shapes and may also be referred to as“annular” alignment components. The particular dimensions can be chosenas desired. In some embodiments, primary alignment component 316 andsecondary alignment component 318 can each have an outer diameter ofabout 54 mm and a radial width of about 4 mm. The outer diameters andradial widths of primary alignment component 316 and secondary alignmentcomponent 318 need not be exactly equal. For instance, the radial widthof secondary alignment component 318 can be slightly less than theradial width of primary alignment component 316 and/or the outerdiameter of secondary alignment component 318 can also be slightly lessthan the radial width of primary alignment component 316 so that, whenin alignment, the inner and outer sides of primary alignment component316 extend beyond the corresponding inner and outer sides of secondaryalignment component 318. Thicknesses (or axial dimensions) of primaryalignment component 316 and secondary alignment component 318 can alsobe chosen as desired. In some embodiments, primary alignment component316 has a thickness of about 1.5 mm while secondary alignment component318 has a thickness of about 0.37 mm. (All numerical values herein areexamples and may be varied as desired.)

Primary alignment component 316 can include a number of sectors, each ofwhich can be formed of a number of primary magnets 326, and secondaryalignment component 318 can include a number of sectors, each of whichcan be formed of a number of secondary magnets 328. In the exampleshown, the number of primary magnets 326 is equal to the number ofsecondary magnets 328, and each sector includes exactly one magnet, butthis is not required; for example, as described below a sector mayinclude multiple magnets. Primary magnets 326 and secondary magnets 328can have arcuate (or curved) shapes in the transverse plane such thatwhen primary magnets 326 (or secondary magnets 328) are positionedadjacent to one another end-to-end, primary magnets 326 (or secondarymagnets 328) form an annular structure as shown. In some embodiments,primary magnets 326 can be in contact with each other at interfaces 330,and secondary magnets 328 can be in contact with each other atinterfaces 332. Alternatively, small gaps or spaces may separateadjacent primary magnets 326 or secondary magnets 328, providing agreater degree of tolerance during manufacturing.

In some embodiments, primary alignment component 316 can also include anannular shield 314 (also referred to as a DC magnetic shield or DCshield) disposed on a distal surface of primary magnets 326. In someembodiments, shield 314 can be formed as a single annular piece ofmaterial and adhered to primary magnets 326 to secure primary magnets326 into position. Shield 314 can be formed of a material that has highmagnetic permeability and/or high magnetic saturation value, such asstainless steel or low-carbon steel, and can redirect magnetic fields toprevent them from propagating beyond the distal side of primaryalignment component 316, thereby protecting sensitive electroniccomponents located beyond the distal side of primary alignment component316 from magnetic interference.

Primary magnets 326 and secondary magnets 328 can be made of a magneticmaterial such as an NdFeB material, other rare earth magnetic materials,or other materials that can be magnetized to create a persistentmagnetic field. Each secondary magnet 328 can have a single magneticregion with a magnetic polarity having a component in the radialdirection in the transverse plane (as shown by magnetic polarityindicator 317 in FIG. 3B). As described below, the magnetic orientationcan be in a radial direction with respect to axis 301 or anotherdirection having a radial component in the transverse plane. Eachprimary magnet 326 can include two magnetic regions having oppositemagnetic orientations. For example, each primary magnet 326 can includean inner arcuate magnetic region 352 having a magnetic orientation in afirst axial direction (as shown by polarity indicator 353 in FIG. 3B),an outer arcuate magnetic region 354 having a magnetic orientation in asecond axial direction opposite the first direction (as shown bypolarity indicator 355 in FIG. 3B), and a central non-magnetized region356 that does not have a magnetic orientation. Central non-magnetizedregion 356 can magnetically separate inner arcuate region 352 from outerarcuate region 354 by inhibiting magnetic fields from directly crossingthrough central region 356. Magnets having regions of opposite magneticorientation separated by a non-magnetized region are sometimes referredto herein as having a “quad-pole” configuration.

In some embodiments, each secondary magnet 328 can be made of a magneticmaterial that has been ground and shaped into an arcuate structure, anda magnetic orientation having a radial component in the transverse planecan be created, e.g., using a magnetizer. Similarly, each primary magnet326 can be made of a single piece of magnetic material that has beenground and shaped into an arcuate structure, and a magnetizer can beapplied to the arcuate structure to induce an axial magnetic orientationin one direction within an inner arcuate region of the structure and anaxial magnetic orientation in the opposite direction within an outerarcuate region of the structure, while demagnetizing or avoidingcreation of a magnetic orientation in the central region. In somealternative embodiments, each primary magnet 326 can be a compoundstructure with two arcuate pieces of magnetic material providing innerarcuate magnetic region 352 and outer arcuate magnetic region 354; insuch embodiments, central non-magnetized region 356 can be formed of anarcuate piece of nonmagnetic (or demagnetized) material or formed as anair gap defined by sidewalls of inner arcuate magnetic region 352 andouter arcuate magnetic region 354. DC shield 314 can be formed of amaterial that has high magnetic permeability and/or high magneticsaturation value, such as stainless steel or low-carbon steel, and canbe plated, e.g., with 5-10 μm of matte Ni. Alternatively, DC shield 314can be formed of a magnetic material having a radial magneticorientation (in the opposite direction of secondary magnets 328). Insome embodiments, DC shield 314 can be omitted entirely.

As shown in FIG. 3B, the magnetic polarity of secondary magnet 328(shown by indicator 317) can be oriented such that when primaryalignment component 316 and secondary alignment component 318 arealigned, the south pole of secondary magnet 328 is oriented toward thenorth pole of inner arcuate magnetic region 352 (shown by indicator 353)while the north pole of secondary magnet 328 is oriented toward thesouth pole of outer arcuate magnetic region 354 (shown by indicator355). Accordingly, the respective magnetic orientations of inner arcuatemagnetic region 352, secondary magnet 328 and outer arcuate magneticregion 356 can generate magnetic fields 340 that exert an attractiveforce between primary magnet 326 and secondary magnet 328, therebyfacilitating alignment between respective electronic devices in whichprimary alignment component 316 and secondary alignment component 318are disposed (e.g., as shown in FIG. 1). Shield 314 can redirect some ofmagnetic fields 340 away from regions below primary magnet 326. Further,the “closed-loop” magnetic field 340 formed around centralnon-magnetized region 356 can have tight and compact field lines that donot stray outside of primary and secondary magnets 326 and 328 as far asmagnetic field 240 strays outside of primary and secondary magnets 226and 228 in FIG. 2B. Thus, magnetically sensitive components can beplaced relatively close to primary alignment component 316 with reducedconcern for stray magnetic fields. Accordingly, as compared to magneticalignment system 200, magnetic alignment system 300 can help to reducethe overall size of a device in which primary alignment component 316 ispositioned and can also help reduce noise created by magnetic field 340in adjacent components or devices, such as an inductive receiver coilpositioned inboard of secondary alignment component 318.

While each primary magnet 326 includes two regions of opposite magneticorientation, it should be understood that the two regions can but neednot provide equal magnetic field strength. For example, outer arcuatemagnetized region 354 can be more strongly polarized than inner arcuatemagnetized region 352. Depending on the particular implementation ofprimary magnets 326, various techniques can be used to create asymmetricpolarization strength. For example, inner arcuate region 352 and outerarcuate region 354 can have different radial widths; increasing radialwidth of a magnetic region increases the field strength of that regiondue to increased volume of magnetic material. Where inner arcuate region352 and outer arcuate region 354 are discrete magnets, magnets havingdifferent magnetic strength can be used.

In some embodiments, having an asymmetric polarization where outerarcuate region 354 is more strongly polarized than inner arcuate region352 can create a flux “sinking” effect toward the outer pole. Thiseffect can be desirable in various situations. For example, when primarymagnet 326 is disposed within a wireless charger device and the wirelesscharger device is used to charge a “legacy” portable electronic devicethat has an inductive receiver coil but does not have a secondary (orany) annular magnetic alignment component, the (DC) magnetic flux fromthe primary annular alignment component may enter a ferrite shieldaround the inductive receiver coil. The DC magnetic flux can contributeto saturating the ferrite shield and reducing charging performance.Providing a primary annular alignment component with a stronger field atthe outer arcuate region than the inner arcuate region can help to drawDC magnetic flux away from the ferrite shield, which can improvecharging performance when a wireless charger device having an annularmagnetic alignment component is used to charge a portable electronicdevice that lacks an annular magnetic alignment component.

It will be appreciated that magnetic alignment system 300 isillustrative and that variations and modifications are possible. Forinstance, while primary alignment component 316 and secondary alignmentcomponent 318 are each shown as being constructed of eight arcuatemagnets, other embodiments may use a different number of magnets, suchas 16 magnets, 18 magnets, 32 magnets, 36 magnets, or any other numberof magnets, and the number of primary magnets need not be equal to thenumber of secondary magnets. In other embodiments, secondary alignmentcomponent 318 can be formed of a single, monolithic annular magnet.Similarly, primary alignment component 316 can be formed of a single,monolithic annular piece of magnetic material with an appropriatemagnetization pattern as described above, or primary alignment component316 can be formed of a monolithic inner annular magnet and a monolithicouter annular magnet, with an annular air gap or region of nonmagneticmaterial disposed between the inner annular magnet and outer annularmagnet. In some embodiments, a construction using multiple arcuatemagnets may improve manufacturing because smaller arcuate magnets areless brittle than a single, monolithic annular magnet and are less proneto yield loss due to physical stresses imposed on the magnetic materialduring manufacturing. It should also be understood that the magneticorientations of the various magnetic alignment components or individualmagnets do not need to align exactly with the lateral and axialdirections. The magnetic orientation can have any angle that provides aclosed-loop path for a magnetic field through the primary and secondaryalignment components.

1.4. Magnetic Orientation for a Closed-Loop Magnetic Alignment System

1.4.1. Radially Symmetric Orientation

As noted above, in embodiments of magnetic alignment systems havingclosed-loop magnetic orientations, such as magnetic alignment system300, secondary alignment component 318 can have a magnetic orientationwith a radial component. For example, in some embodiments, secondaryalignment component 318 can have a magnetic polarity in a radialorientation. FIG. 4 shows a simplified top-down view of a secondaryalignment component 418 according to some embodiments. Secondaryalignment component 418, like secondary alignment component 318, can beformed of arcuate magnets 428 a-h having radial magnetic orientations asshown by magnetic polarity indicators 417 a-h. In this example, eacharcuate magnet 428 a-h has a north magnetic pole oriented toward theradially outward side and a south magnetic pole toward the radiallyinward side; however, this orientation can be reversed, and the northmagnetic pole of each arcuate magnet 428 a-h can be oriented toward theradially inward side while the south magnetic pole is oriented towardthe radially outward side.

FIG. 5A shows a perspective view of a magnetic alignment system 500according to some embodiments. Magnetic alignment system 500, which canbe an implementation of magnetic alignment system 300, includes asecondary alignment component 518 having a radially outward magneticorientation (e.g., as shown in FIG. 4) and a complementary primaryalignment component 516. In this example, magnetic alignment system 500includes a gap 507 between two of the sectors; however, gap 507 isoptional and magnetic alignment system 500 can be a complete annularstructure. Also shown are components 502, which can include, for examplean inductive coil assembly or other components located within thecentral region of primary magnetic alignment component 516 or secondarymagnetic alignment component 518. Magnetic alignment system 500 can havea closed-loop configuration similar to magnetic alignment system 300 (asshown in FIG. 3B) and can include arcuate sectors 501, each of which canbe made of one or more arcuate magnets. In some embodiments, theclosed-loop configuration of magnetic alignment system 500 can reduce orprevent magnetic field leakage that may affect components 502.

FIG. 5B shows an axial cross-section view through one of arcuate sectors501. Arcuate sector 501 includes a primary magnet 526 and a secondarymagnet 528. As shown by orientation indicator 517, secondary magnet 528has a magnetic polarity oriented in a radially outward direction, i.e.,the north magnetic pole is toward the radially outward side of magneticalignment system 500. Like primary magnets 326 described above, primarymagnet 526 includes an inner arcuate magnetic region 552, an outerarcuate magnetic region 554, and a central non-magnetized region 556(which can include, e.g., an air gap or a region of nonmagnetic ornon-magnetized material). Inner arcuate magnetic region 552 has amagnetic polarity oriented axially such that the north magnetic pole istoward secondary magnet 528, as shown by indicator 553, while outerarcuate magnetic region 554 has an opposite magnetic orientation, withthe south magnetic pole oriented toward secondary magnet 528, as shownby indicator 555. As described above with reference to FIG. 3B, thearrangement of magnetic orientations shown in FIG. 5B results inmagnetic attraction between primary magnet 526 and secondary magnet 528.In some embodiments, the magnetic polarities can be reversed such thatthe north magnetic pole of secondary magnet 528 is oriented toward theradially inward side of magnetic alignment system 500, the northmagnetic pole of outer arcuate region 554 of primary magnet 526 isoriented toward secondary magnet 528, and the north magnetic pole ofinner arcuate region 552 is oriented away from secondary magnet 528.

When primary alignment component 516 and secondary alignment component518 are aligned, the radially symmetrical arrangement and directionalequivalence of magnetic polarities of primary alignment component 516and secondary alignment component 518 allow secondary alignmentcomponent 518 to rotate freely (relative to primary alignment component516) in the clockwise or counterclockwise direction in the lateral planewhile maintaining alignment along the axis.

As used herein, a “radial” orientation need not be exactly or purelyradial. For example, FIG. 5C shows a secondary arcuate magnet 538according to some embodiments. Secondary arcuate magnet 538 has a purelyradial magnetic orientation, as indicated by arrows 539. Each arrow 539is directed at the center of curvature of magnet 538; if extendedinward, arrows 539 would converge at the center of curvature. However,achieving this purely radial magnetization requires that magneticdomains within magnet 538 be oriented obliquely to neighboring magneticdomains. For some types of magnetic materials, purely radial magneticorientation may not be practical. Accordingly, some embodiments use a“pseudo-radial” magnetic orientation that approximates the purely radialorientation of FIG. 5C. FIG. 5D shows a secondary arcuate magnet 548with pseudo-radial magnetic orientation according to some embodiments.Magnet 548 has a magnetic orientation, shown by arrows 549, that isperpendicular to a baseline 551 connecting the inner corners 552, 553 ofarcuate magnet 548. If extended inward, arrows 549 would not converge.Thus, neighboring magnetic domains in magnet 548 are parallel to eachother, which is readily achievable in magnetic materials such as NdFeB.The overall effect in a magnetic alignment system, however, can besimilar to the purely radial magnetic orientation shown FIG. 5C. FIG. 5Eshows a secondary annular alignment component 558 made up of magnets 548according to some embodiments. Magnetic orientation arrows 549 have beenextended to the center point 561 of annular alignment component 558. Asshown the magnetic field direction can be approximately radial, with thecloseness of the approximation depending on the number of magnets 548and the inner radius of annular alignment component 558. In someembodiments, 18 magnets 548 can provide a pseudo-radial orientation; inother embodiments, more or fewer magnets can be used. It should beunderstood that all references herein to magnets having a “radial”magnetic orientation include pseudo-radial magnetic orientations andother magnetic orientations that are approximately but not purelyradial.

In some embodiments, a radial magnetic orientation in a secondaryalignment component 518 (e.g., as shown in FIG. 5B) provides a magneticforce profile between secondary alignment component 518 and primaryalignment component 516 that is the same around the entire circumferenceof the magnetic alignment system. The radial magnetic orientation canalso result in greater magnetic permeance, which allows secondaryalignment component 518 to resist demagnetization as well as enhancingthe attractive force in the axial direction and improving shear force inthe lateral directions when the two components are aligned.

FIGS. 6A and 6B show graphs of force profiles for different magneticalignment systems, according to some embodiments. Specifically, FIG. 6Ashows a graph 600 of vertical attractive (normal) force in the axial (z)direction for different magnetic alignment systems of comparable sizeand using similar types of magnets. Graph 600 has a horizontal axisrepresenting displacement from a center of alignment, where 0 representsthe aligned position and negative and positive values representdisplacements from the aligned position in opposite directions (inarbitrary units), and a vertical axis showing the normal force(F_(NORMAL)) as a function of displacement in the lateral plane (also inarbitrary units). For purposes of this description, F_(NORMAL) isdefined as the magnetic force between the primary and secondaryalignment components in the axial direction; F_(NORMAL)>0 representsattractive force while F_(NORMAL)<0 represents repulsive force. Graph600 shows normal force profiles for three different types of magneticalignment systems. A first type of magnetic alignment system uses“central” alignment components, such as a pair of complementarydisc-shaped magnets placed along an axis; a representative normal forceprofile for a central magnetic alignment system is shown as line 601(dot-dash line). A second type of magnetic alignment system uses annularalignment components with axial magnetic orientations, e.g., magneticalignment system 200 of FIGS. 2A and 2B; a representative normal forceprofile for such an annular-axial magnetic alignment system is shown asline 603 (dashed line). A third type of magnetic alignment system usesannular alignment components with closed-loop magnetic orientations andradial symmetry (e.g., magnetic alignment system 500 of FIGS. 5A and5B); a representative normal force profile for a radially symmetricclosed-loop magnetic alignment system is shown as line 605 (solid line).

Similarly, FIG. 6B shows a graph 620 of lateral (shear) force in atransverse direction for different magnetic alignment systems. Graph 620has a horizontal axis representing lateral displacement in opposingdirections from a center of alignment, using the same convention asgraph 600, and a vertical axis showing the shear force (F_(SHEAR)) as afunction of direction (in arbitrary units). For purposes of thisdescription, F_(SHEAR) is defined as the magnetic force between theprimary and secondary alignment components in the lateral direction;F_(SHEAR)>0 represents force toward the left along the displacement axiswhile F_(SHEAR)<0 represents force toward the right along thedisplacement axis. Graph 620 shows shear force profiles for the samethree types of magnetic alignment systems as graph 600: a representativeshear force profile for a central magnetic alignment system is shown asline 621 (dot-dash line); a representative shear force profile for anannular-axial magnetic alignment system is shown as line 623 (dashedline); and a representative normal force profile for a radiallysymmetric closed-loop magnetic alignment system is shown as line 625(solid line).

As shown in FIG. 6A, each type of magnetic alignment system achieves thestrongest magnetic attraction in the axial direction (i.e., normalforce) when the primary and secondary alignment components are in thealigned position (0 on the horizontal axis), as shown by respectivepeaks 611, 613, and 615. While the most strongly attractive normal forceis achieved in the aligned positioned for all systems, the magnitude ofthe peak depends on the type of magnetic alignment system. Inparticular, a radially-symmetric closed-loop magnetic alignment system(e.g., magnetic alignment system 500 of FIG. 5) provides strongermagnetic attraction when in the aligned position than the other types ofmagnetic alignment systems. This strong attractive normal force canovercome small misalignments and can help to hold devices in the alignedposition, thereby can achieving a more accurate and robust alignmentbetween the primary and secondary alignment components, which in turncan provide a more accurate and robust alignment between a portableelectronic device and a wireless charger device within which themagnetic alignment system is implemented.

As shown in FIG. 6B, the strongest shear forces are obtained when theprimary and secondary alignment components are laterally just outside ofthe aligned position, e.g., at −2 and +2 units of separation from thealigned position, as shown by respective peaks 631 a-b, 633 a-b, and 635a-b. These shear forces act to urge the alignment components toward thealigned position. Similarly to the normal force, the peak strength ofshear force depends on the type of magnetic alignment system. Inparticular, a radially-symmetric closed-loop magnetic alignment system(e.g., magnetic alignment system 500 of FIG. 5) provides highermagnitude of shear force when just outside of the aligned position thanthe other types of magnetic alignment systems. This strong shear forcecan provide tactile feedback (sometimes described as a sensation of“snappiness”) to help the user identify when the two components arealigned. In addition, like the normal force, the shear force canovercome small misalignments due to frictional force and can achieve amore accurate and robust alignment between the primary and secondaryalignment components, which in turn can provide a more accurate androbust alignment between a portable electronic device and a wirelesscharger device within which the magnetic alignment system isimplemented.

Depending on the particular configuration of magnets, various designchoices can be used to increase the sensation of snappiness for aclosed-loop magnetic alignment system. For example, reducing the amountof magnetic material in the devices in areas near the magnetic alignmentcomponents—e.g., by using less material or by increasing the distancebetween the magnetic alignment component and the other magneticmaterial—can reduce stray fields and increase the perceived “snapping”effect of the magnetic alignment components. As another example,increasing the magnetic-field strength of the alignment magnets (e.g.,by increasing the amount of material) can increase both shear and normalforces. As yet another example, the widths of the magnetized regions inthe primary annular alignment component (and/or the relative strength ofthe magnetic field in each region) can be optimized based on theparticular magnetic orientation pattern for the secondary annularalignment component (e.g., whether the secondary annular alignmentcomponents have the purely radial magnetic orientation of FIG. 5C or thepseudo-radial magnetic orientation of FIG. 5D). Another considerationcan be the coefficient of friction between the surfaces of the devicescontaining primary and secondary alignment components; lower frictiondecreases resistance to the shear force exerted by the annular magneticalignment components.

A radially-symmetric closed-loop magnetic alignment system (e.g.,magnetic alignment system 500 of FIGS. 5A and 5B) can provide accurateand robust alignment in the axial and lateral directions. Further,because of the radial symmetry, the alignment system does not have apreferred rotational orientation in the lateral plane about the axis;the shear force profile can be the same regardless of relativerotational orientation of the electronic devices being aligned.

1.4.2. Alternating Radial Orientation

In some embodiments, a closed-loop magnetic alignment system can bedesigned to provide one or more preferred rotational orientations. FIG.7 shows a simplified top-down view of a secondary alignment component718 according to some embodiments. Secondary alignment component 718includes sectors 728 a-h having radial magnetic orientations as shown bymagnetic polarity indicators 717 a-h. Each of sectors 728 a-h caninclude one or more secondary arcuate magnets. In this example,secondary magnets in sectors 728 b, 728 d, 728 f, and 728 h each have anorth magnetic pole oriented toward the radially outward side and asouth magnetic pole toward the radially inward side, while secondarymagnets in sectors 728 a, 728 c, 728 e, and 728 g each have a northmagnetic pole oriented toward the radially inward side and a southmagnetic pole toward the radially outward side. In other words, magnetsin adjacent sectors 728 a-h of secondary alignment component 718 havealternating magnetic orientations.

A complementary primary alignment component can have sectors withcorrespondingly alternating magnetic orientations. For example, FIG. 8Ashows a perspective view of a magnetic alignment system 800 according tosome embodiments. Magnetic alignment system 800 includes a secondaryalignment component 818 having alternating radial magnetic orientations(e.g., as shown in FIG. 7) and a complementary primary alignmentcomponent 816. Some of the arcuate sections of magnetic alignment system800 are not shown in order to reveal internal structure; however, itshould be understood that magnetic alignment system 800 can be acomplete annular structure. Also shown are components 802, which caninclude, for example, inductive coil assemblies or other componentslocated within the central region of primary annular alignment component816 and/or secondary annular alignment component 818. Magnetic alignmentsystem 800 can be a closed-loop magnetic alignment system similar tomagnetic alignment system 300 described above and can include arcuatesectors 801 b, 801 c of alternating magnetic orientations, with eacharcuate sector 801 b, 801 c including one or more arcuate magnets ineach of primary annular alignment component 816 and secondary annularalignment component 818. In some embodiments, the closed-loopconfiguration of magnetic alignment system 800 can reduce or preventmagnetic field leakage that may affect component 802. Like magneticalignment system 500, magnetic alignment system 800 can include a gap803 between two sectors.

FIG. 8B shows an axial cross-section view through one of arcuate sectors801 b, and FIG. 8C shows an axial cross-section view through one ofarcuate sectors 801 c. Arcuate sector 801 b includes a primary magnet826 b and a secondary magnet 828 b. As shown by orientation indicator817 b, secondary magnet 828 b has a magnetic polarity oriented in aradially outward direction, i.e., the north magnetic pole is toward theradially outward side of magnetic alignment system 800. Like primarymagnets 326 described above, primary magnet 826 b includes an innerarcuate magnetic region 852 b, an outer arcuate magnetic region 854 b,and a central non-magnetized region 856 b (which can include, e.g., anair gap or a region of nonmagnetic or non-magnetized material). Innerarcuate magnetic region 852 b has a magnetic polarity oriented axiallysuch that the north magnetic pole is toward secondary magnet 828 b, asshown by indicator 853 b, while outer arcuate magnetic region 854 b hasan opposite magnetic orientation, with the south magnetic pole orientedtoward secondary magnet 828 b, as shown by indicator 855 b. As describedabove with reference to FIG. 3B, the arrangement of magneticorientations shown in FIG. 8B results in magnetic attraction betweenprimary magnet 826 b and secondary magnet 828 b.

As shown in FIG. 8C, arcuate sector 801 c has a “reversed” magneticorientation relative to arcuate sector 801 b. Arcuate sector 801 cincludes a primary magnet 826 c and a secondary magnet 828 c. As shownby orientation indicator 817 c, secondary magnet 828 c has a magneticpolarity oriented in a radially inward direction, i.e., the northmagnetic pole is toward the radially inward side of magnetic alignmentsystem 800. Like primary magnets 326 described above, primary magnet 826c includes an inner arcuate magnetic region 852 c, an outer arcuatemagnetic region 854 c, and a central non-magnetized region 856 c (whichcan include, e.g., an air gap or a region of nonmagnetic ornon-magnetized material). Inner arcuate magnetic region 852 c has amagnetic polarity oriented axially such that the south magnetic pole istoward secondary magnet 828 c, as shown by indicator 853 c, while outerarcuate magnetic region 854 c has an opposite magnetic orientation, withthe north magnetic pole oriented toward secondary magnet 828 c, as shownby indicator 855 c. As described above with reference to FIG. 3B, thearrangement of magnetic orientations shown in FIG. 8C results inmagnetic attraction between primary magnet 826 c and secondary magnet828 c.

An alternating arrangement of magnetic polarities as shown in FIGS. 7and 8A-8C can create a “ratcheting” feel when secondary alignmentcomponent 818 is aligned with primary alignment component 816 and one ofalignment components 816, 818 is rotated relative to the other about thecommon axis. For instance, as secondary alignment component 816 isrotated relative to primary alignment component 816, eachradially-outward magnet 828 b alternately comes into proximity with acomplementary magnet 826 b of primary alignment component 816, resultingin an attractive magnetic force, or with an anti-complementary magnet826 c of primary alignment component 816, resulting in a repulsivemagnetic force. If primary magnets 826 b, 826 c and secondary magnets828 b, 828 c have the same angular size and spacing, in any givenorientation, each pair of magnets will experience similar net(attractive or repulsive) magnetic forces such that alignment is stableand robust in rotational orientations in which complementary magnetpairs 826 b, 828 b and 826 c, 828 c are in proximity. In otherrotational orientations, a torque toward a stable rotational orientationcan be experienced.

In the examples shown in FIGS. 7 and 8A-8C, each sector includes onemagnet, and the direction of magnetic orientation alternates with eachmagnet. In some embodiments, a sector can include two or more magnetshaving the same direction of magnetic orientation. For example, FIG. 9Ashows a simplified top-down view of a secondary alignment component 918according to some embodiments. Secondary alignment component 918includes secondary magnets 928 b with radially outward magneticorientations and secondary magnets 928 c with radially inwardorientations, similarly to secondary alignment component 818 describedabove. In this example, the magnets are arranged such that a pair ofoutwardly-oriented magnets 928 b (forming a first sector 901) areadjacent to a pair of inwardly-oriented magnets 928 c (forming a secondsector 903 adjacent to first sector 901). The pattern of alternatingsectors (with two magnets per sector) repeats around the circumferenceof secondary alignment component 918. Similarly, FIG. 9B shows asimplified top-down view of another secondary alignment component 918′according to some embodiments. Secondary alignment component 918′includes secondary magnets 928 b with radially outward magneticorientations and secondary magnets 928 c with radially inwardorientations. In this example, the magnets are arranged such that agroup of four radially-outward magnets 928 b (forming a first sector911) is adjacent to a group of four radially-inward magnets 928 c(forming a second sector 913 adjacent to first sector 911). The patternof alternating sectors (with four magnets per sector) repeats around thecircumference of secondary alignment component 918′. Although not shownin FIGS. 9A and 9B, the structure of a complementary primary alignmentcomponent for secondary alignment component 918 or 918′ should beapparent in view of FIGS. 8A-8C. A shear force profile for the alignmentcomponents of FIGS. 9A and 9B can be similar to the ratcheting profiledescribed above, although the number of rotational orientations thatprovide stable alignment will be different.

1.4.3. Other Magnetic Orientations

In other embodiments, a variety of force profiles can be created bychanging the magnetic orientations of different sectors within theprimary and/or secondary alignment components. As just one example, FIG.10 shows a simplified top-down view of a secondary alignment component1018 according to some embodiments. Secondary alignment component hassectors 1028 a-h with sector-dependent magnetic orientations as shown bymagnetic polarity indicators 1017 a-h. In this example, secondaryalignment component 1018 can be regarded as bisected by bisector line1001, which defines two halves of secondary alignment component 1018. Ina first half 1003, sectors 1028 e-h have magnetic polarities orientedradially outward, similarly to examples described above.

In the second half 1005, sectors 1028 a-d have magnetic polaritiesoriented substantially parallel to bisector line 1001 rather thanradially. In particular, sectors 1028 a and 1028 b have magneticpolarities oriented in a first direction parallel to bisector line 1001,while sectors 1028 c and 1028 d have magnetic polarities oriented in thedirection opposite to the direction of the magnetic polarities ofsectors 1028 a and 1028 b. A complementary primary alignment componentcan have an inner annular region with magnetic north pole orientedtoward secondary alignment component 1018, an outer annular region withmagnetic north pole oriented away from secondary alignment component1018, and a central non-magnetized region, providing a closed-loopmagnetic orientation as described above. The asymmetric arrangement ofmagnetic orientations in secondary alignment component 1018 can modifythe shear force profile such that secondary alignment component 1018generates less shear force resisting motion in the direction towardsecond half 1005 (upward in the drawing) than in the direction towardfirst half 1003 (downward in the drawing). In some embodiments, anasymmetrical arrangement of this kind can be used where the primaryalignment component is mounted in a docking station and the secondaryalignment component is mounted in a portable electronic device thatdocks with the docking station. Assuming secondary annular alignmentcomponent 1018 is oriented in the portable electronic device such thathalf-annulus 1005 is toward the top of the portable electronic device,the asymmetric shear force can facilitate an action of sliding theportable electronic device downward to dock with the docking station orupward to remove it from the docking station, while still providing anattractive force to draw the portable electronic device into a desiredalignment with the docking station.

In the embodiments described above, the secondary annular magneticalignment component has a magnetic orientation that is generally alignedin the transverse plane. In some alternative embodiments, a secondaryannular magnetic alignment component can instead have a quad-poleconfiguration similar to that of primary annular magnetic alignmentcomponent 316 of FIGS. 3A and 3B, with or without a DC shield (which, ifpresent, can be similar to DC shield 314 of FIGS. 3A and 3B) on thedistal surface of the secondary arcuate magnets. Using quad-polemagnetic configurations in both the primary and secondary alignmentcomponents can provide a closed-loop DC magnetic flux path and a strongsensation of “snappiness”; however, the thickness of the secondarymagnetic alignment component may need to be increased to accommodate thequad-pole magnets and DC shield, which may increase the overallthickness of a portable electronic device that houses the secondarymagnetic alignment component. To reduce thickness, the DC shield on thedistal surface of the secondary alignment component can be omitted;however, omitting the DC shield may result in increased flux leakageinto neighboring components.

It will be appreciated that the foregoing examples are illustrative andnot limiting. Sectors of a primary and/or secondary alignment componentcan include magnetic elements with the magnetic polarity oriented in anydesired direction and in any combination, provided that the primary andsecondary alignment components of a given magnetic alignment system havecomplementary magnetic orientations that exert forces toward the desiredposition of alignment. Different combinations of magnetic orientationsmay create different shear force profiles, and the selection of magneticorientations may be made based on a desired shear force profile (e.g.,high snappiness), avoidance of DC flux leakage into other components,and other design considerations.

1.5. Annular Magnetic Alignment Components with Gaps

In examples described above, the primary alignment component andsecondary alignment component have annular shapes. As described above(e.g., with reference to FIG. 3A), the annulus can be completely closed.In other embodiments (e.g., as shown in FIGS. 5A and 8A), a primary orsecondary annular alignment component can include one or more gaps,where each gap can be a section of an annulus where magnetic material(or indeed any material) is absent.

FIG. 11 illustrates an example of an alignment component 1118 (which canbe a primary or secondary annular magnetic alignment component) having agap according to some embodiments. As shown, alignment component 1118can include a number of arcuate magnets 1128 forming an annular shape.In this embodiment, a gap 1101 between two magnets is created byomitting one of arcuate magnets 1128. More generally, a gap such as gap1101 can be created using various techniques. For example, the angle ϕsubtended by each arcuate magnet can be selected such that 360°/ϕ is notan integer. Thus, the size of gap 1101 may be equal to or smaller than(or larger than) the size of an arcuate magnet 1128. In variousembodiments of a magnetic alignment system, a gap such as gap 1101 maybe formed in either or both of a secondary alignment component and aprimary alignment component, and the size, number, and location of gapscan be different between the primary and secondary alignment components.To provide reliable magnetic alignment, the size of gap 1101 or othergaps can be limited, e.g., to 20° of arc or less.

In some embodiments, a gap such as gap 1101 may provide a convenientpath for electrical connections to components located in interior region1103 inboard of alignment component 1118. For example, as describedabove, an inductive coil (or other electronic component) may be disposedin interior region 1103, and gap 1101 in alignment component 1118 mayprovide a convenient path for electrical connections between theinductive coil (or other component) and a battery (or other components)located outboard of alignment component 1118. It should be understoodthat electrical connections can also be made by routing connection pathsover or under magnets 1128 (into or out of the plane of FIG. 11);however, routing connection paths over or under the magnets may resultin increased thickness of the device in which alignment component 1118is disposed.

It should be understood that a gap such as gap 1101 can be included in aprimary alignment component, a secondary alignment component, or both.In some embodiments where gaps are provided in both the primaryalignment component and the secondary alignment component, the presenceof the gaps may alter the shear force profile in a manner that creates apreferred rotational orientation. The extent to which a preferredorientation arises may depend on the size of the gaps and the particularconfiguration of magnets.

1.6. Portable Electronic Devices Incorporating Magnetic AlignmentComponents

FIGS. 12A and 12B show simplified rear views of portable electronicdevices incorporating magnetic alignment components according to someembodiments. In the examples shown, the portable electronic devicesincorporate secondary magnetic alignment components having a radialmagnetic orientation, which can allow for a thinner device profile;however, it should be understood that a portable electronic device caninstead incorporate a primary magnetic alignment component.

FIG. 12A shows a smart phone 1200 as an example of a portable electronicdevice that can incorporate a magnetic alignment component according tosome embodiments. Smart phone 1200 can support a variety of computingand communication activities and can draw operating power from anonboard battery (not shown). In some embodiments, the battery can berecharged using wireless power transfer. For example, smart phone 1200can include a coil assembly 1210, which can be configured as aninductive receiver coil for wireless power transfer. Such time-varyingmagnetic fields can be provided by a transmitter coil in a wirelesscharger device (not shown in FIG. 12A). In addition or instead, coilassembly 1210 may be operable as an inductive transmitter coil forwireless power transfer and may be operable to generate time-varyingmagnetic fields that can be used to charge an accessory device such as awireless headset, an external battery, or another portable electronicdevice (e.g., another smart phone). Coil assembly 1210 can include aninductive receiver coil (e.g., a wound coil of electrically conductivewire) coupled to a power storage device (e.g., a battery) or powerconsuming device. In some embodiments, coil assembly 1210 can alsoinclude electromagnetic shielding (e.g., one or more pieces of ferrite)placed over the distal surface, inner annular surface, and/or outerannular surface of the coil.

For optimal wireless charging performance, it is desirable to align coil1210 with a coil in the transmitting (or receiving) device. Annularmagnetic alignment component 1218 can be, for example, an implementationof any of the secondary magnetic alignment components described aboveand can include an annular arrangement of magnets 1228 with interfaces1232, which can be air gaps or surfaces where adjacent magnets contactone another. The magnetic polarities of magnets 1228 can be oriented invarying directions in the lateral plane, e.g., in a radial direction asdescribed above with reference to FIG. 4. In the example shown, magneticalignment component 1218 includes a gap 1201, which can provideelectrical connection paths for wires (or conductive traces) to connectbetween coil 1210 and components outboard of magnetic alignmentcomponent 1218.

Coil 1210 can be optimized to support wireless power transfer betweendevices. In some embodiments, it may also be desirable to supportwireless data transfer between devices, for instance to allow differentdevices that incorporate magnetic alignment systems to identifythemselves. Accordingly, in some embodiments, a near-field communication(NFC) coil 1260 can be provided in the region between coil 1210 andmagnets 1228. An NFC reader circuit and/or other components (not shown)can connect to termination ends 1262 a, 1226 b of NFC coil 1260 throughgap 1201. Example embodiments of NFC coil 1210 are described in section5 below.

In some embodiments, a magnetic alignment component such as component1218 can be modified to fit portable electronic devices of differentsizes while preserving a constant outer diameter and radial width of theannulus. By way of example, FIG. 12B shows a smart phone 1200′ asanother example of a portable electronic device that can incorporate amagnetic alignment component according to some embodiments. Like smartphone 1200 of FIG. 12A, smart phone 1200′ can support a variety ofcomputing and communication activities and may draw operating power froman onboard battery (not shown). One difference between smart phone 1200and smart phone 1200′ can be that smart phone 1200′ has a smaller formfactor than smart phone 1200. For instance smart phone 1200′ may benarrower (in the x direction) and/or shorter (in the y direction) thansmart phone 1200. However, it may be desirable for these smart phones ofdifferent form factors to interoperate with the same wireless chargerdevices and/or other accessories. Accordingly, smart phone 1200′ caninclude a wireless charging coil 1210′ that can be identical to wirelesscharging coil 1210 of smart phone 1200.

To provide alignment of coil 1210′ with a coil in another device, smartphone 1200′ can include a magnetic alignment component 1218′. Magneticalignment component 1218′ can be for example, an implementation of anyof the secondary magnetic alignment components described above and caninclude an annular arrangement of arcuate magnets 1228′ with interfaces1232′, which can be air gaps or surfaces where adjacent magnets 1228′contact one another. The magnetic polarities of magnets 1228′ can beoriented in varying directions in the lateral plane, e.g., in a radialdirection as described above. In addition, NFC coil 1260′ can beprovided in the region between coil 1210′ and magnets 1228′, similarlyto NFC coil 1260 of FIG. 12A.

In the example shown, to accommodate the narrower width of smart phone1200′ magnetic alignment component 1218′ includes diametrically opposedgaps 1201 a, 1201 b. In addition to decreasing the width (in the xdirection) of magnetic alignment component 1218′, gaps 1201 a and/or1201 b can also provide electrical connection paths for wires (orconductive traces) to connect between coil 1210′ and components outboardof magnetic alignment component 1218′. In some embodiments, the arcuatemagnet sections 1228′ adjacent to gaps 1201 a, 1201 b can have beveledcorners 1229 a-b and 1231 a-b, which can further reduce the width ofalignment component 1218′ without reducing the outer diameter.

It should be understood that smart phones 1200 and 1200′ are justexamples, and a variety of portable electronic devices having a range ofdifferent form factors can accommodate an annular alignment component ofa given diameter and width. Further, while FIGS. 12A and 12B showalignment components 1218, 1218′ and coils 1210, 1210′ on the rear ofsmart phones 1200, 1200′, it should be understood that these componentscan be inside the rear housing of smart phones 1200, 1200′ and that therear housing may be opaque so that alignment components 1218, 1218′ andcoils 1210, 1210′ need not be visible to users.

1.7. Wireless Charger Devices Incorporating Magnetic AlignmentComponents

FIG. 13 shows a simplified view of a wireless charger device 1300incorporating a magnetic alignment component according to someembodiments. In the example shown, the wireless charger deviceincorporates a primary alignment component; however, it should beunderstood that a wireless charger device can instead incorporate asecondary magnetic alignment component.

Wireless charger device 1300 can support inductive power transfer forcharging a portable electronic device (such as smart phone 1200 of FIG.12A or smart phone 1200′ of FIG. 12B). In this example, wireless chargerdevice 1300 has a housing 1302 surrounding a transmitter coil assembly1312. Although not shown in FIG. 13, it should be understood thattransmitter coil assembly 1312 can include an inductive transmitter coilhaving wires that can be connected to an external power source (e.g.,via cable 1304). In some embodiments, transmitter coil assembly 1312 canalso include electromagnetic shielding (e.g., one or more pieces offerrite placed over the distal surface, inner annular surface, and/orouter annular surface of the transmitter coil and/or a thin layer ofmetal placed over the proximal surface of the transmitter coil to reduceparasitic electric fields). Control circuitry to control the transmittercoil can be disposed within housing 1302 or elsewhere as desired. Aprimary magnetic alignment component 1316 is disposed around transmittercoil assembly 1312.

Components of wireless charger device 1300 can be enclosed in housing1302, which can be made of aluminum, plastic, ceramic, or other durablematerial. Housing 1302 is shown as puck-shaped; however, other shapescan also be used. For instance, housing 1302 can be rectangular,elliptical, or any other shape that provides a charging surface. In someembodiments, housing 1302 can be a two-piece housing that includes anenclosure for the distal and side surfaces of wireless charger device1300 and a top cap covering the proximal surface of transmitter coilassembly 1312. The top cap (not shown in FIG. 13) can be made of ceramicor other material that is permeable to electromagnetic fields, while theenclosure can be made of aluminum, plastic or other materials. The topcap and enclosure can be sealed together using an appropriate adhesive.Although FIG. 13 shows a view into the interior of wireless chargerdevice 1300, it should be understood that housing 1302 can be opaque.Housing 1302 can include an opening to permit connection of cable 1304to transmitter coil assembly 1312. In some embodiments, one end of cable1304 is captively coupled to electronic components of transmitter coilassembly 1312 while the other end of cable 1304 (not shown) is coupledto a plug connector (e.g., a USB type A or USB-C connector) that can beused to draw power from the grid or other power source via an adapter.

For optimal wireless charging performance, it is desirable to align thetransmitter coil of coil assembly 1312 with a corresponding coil in areceiving device such as smart phone 1200. Magnetic alignment component1316 can be, for example, an implementation of any of the primarymagnetic alignment components described above and can include an annulararrangement of magnets 1326 with interfaces 1330 between adjacentmagnets 1326, which can be air gaps or surfaces where adjacent magnets1326 contact one another. Magnets 1326 can provide a closed loopconfiguration as described above; for instance, each magnet 1326 caninclude an inner arcuate region having an axial magnetic orientation ina first direction, an outer arcuate region having an axial magneticorientation in a second direction opposite the first direction, and acentral arcuate region having no distinct magnetic orientation. In theexample shown, magnetic alignment component 1316 includes a gap 1301,which can provide electrical connection paths for wires (or conductivetraces) to connect between coil assembly 1312 and cable 1304 withoutadding to the axial thickness of wireless charger device 1300.

Coil assembly 1312 can be optimized to support wireless power transferbetween devices. In some embodiments, it may also be desirable tosupport wireless data transfer between devices, for instance to allowdifferent devices that incorporate magnetic alignment systems toidentify themselves. Accordingly, in some embodiments, a near-fieldcommunication (NFC) coil 1364 can be provided in the region between coilassembly 1312 and magnetic alignment component 1316. In someembodiments, NFC coil 1364 can couple to a passive NFC tag that can beread by a suitably configured NFC reader (e.g., in smart phone 1200 ofFIG. 12A). Example embodiments of NFC coil 1364 are described in section5 below.

In various embodiments, primary magnetic alignment component 1316 can beused to facilitate alignment between wireless charger device 1300 and avariety of different portable electronic devices having different formfactors (e.g., including portable electronic device 1200 and portableelectronic device 1200′). As long as the portable electronic devicebeing aligned with primary magnetic alignment component 1316 includes acomplementary secondary alignment component having an annular shapematching primary alignment component 1316 and a magnetic fieldorientation complementary to primary alignment component 1316, primaryalignment component 1316 can facilitate alignment of wireless chargerdevice 1300 with the portable electronic device, regardless of any otherdimensions of either device. It should also be understood that someembodiments of wireless charger device 1300 can be used to charge aportable electronic device that does not have a magnetic alignmentcomponent; however, in such instances, primary alignment component 1316might not facilitate optimal alignment with the portable electronicdevice, and the user would need to align the devices using othertechniques (e.g., manual adjustment based on charging performance orplacing the devices in a cradle that holds the devices such that theirrespective charging coils are in alignment).

1.8. Wireless Charging Systems with Magnetic Alignment

FIG. 14A shows a simplified perspective view of a system 1400 includingportable electronic device 1200 (of FIG. 12A) in alignment with wirelesscharger device 1300 (of FIG. 13) according to some embodiments. In FIG.14A, portions of wireless charger device 1300 are shown using dashedlines to avoid obscuring other details. As shown, wireless chargerdevice 1300 can be placed with its charging (or proximal) surfaceagainst the rear (or proximal) surface 1403 of portable electronicdevice 1200. When the devices are placed in this arrangement, secondaryalignment component 1218 in portable electronic device 1200 can attractand hold primary magnetic alignment component 1316 of wireless chargerdevice 1300 in alignment so that transmitter coil assembly 1312 ofwireless charger device 1300 is aligned with coil assembly 1210 ofportable electronic device 1200. As shown, wireless charger device 1300can have any rotational orientation about an axis defined by the centersof primary magnetic alignment component 1316 and secondary magneticalignment component 1218; for instance gap 1201 in secondary magneticalignment component 1218 need not align with gap 1301 in primarymagnetic alignment component 1316.

FIG. 14B shows a simplified partial cross section view of system 1400according to some embodiments. Portable electronic device 1200 has arear housing 1402 (which can be made of a material such as glass orplastic that is permeable to electromagnetic fields and to DC magneticfields) and a front housing 1404 (which can include a touch screendisplay). Coil assembly 1210 can include an inductive receiver coil 1410(which can be made, e.g., of stranded wire wound into a coil) andshielding 1412 (which can include, e.g., a ferrimagnetic shield).Secondary magnet 1428 forms a portion of secondary magnetic alignmentcomponent 1218 and can have a magnetic field oriented in a radiallyinward direction (as shown by the arrow). It should be understood that,although alignment component 1218 is shown in FIG. 14A, rear housing1402 can be opaque and alignment component 1218 need not be visible to auser.

Wireless charger device 1300 has a housing 1302 that includes asingle-piece enclosure 1406 forming distal and side surfaces of housing1302 and a top cap 1408 forming a proximal surface of housing 1302. Asdescribed above, enclosure 1406 and top cap 1408 can be made of the samematerial or different materials, and top cap 1408 can be made of amaterial that is permeable to AC electromagnetic fields and to DCmagnetic fields. Transmitter coil assembly 1312 can include an inductivetransmitter coil 1416 (which can be made, e.g., of stranded wire woundinto a coil) and electromagnetic shielding 1415 (which can include,e.g., a ferrimagnetic shield). Primary magnet 1426 forms a portion ofprimary magnetic alignment component 1316 and can include an innerarcuate region 1452 having a magnetic field oriented in a first axialdirection, an outer arcuate region 1454 having a magnetic field orientedin a second axial direction opposite the first axial direction, and anon-magnetized central arcuate region 1456. As described above, a DCshield 1414 can be disposed on the distal surface of primary magnet1426. It should be understood that, although alignment component 1316 isshown in FIG. 14A, housing 1302 can be opaque and alignment component1316 need not be visible to a user.

When aligned, primary magnet 1426 and secondary magnet 1428 produce aclosed-loop magnetic flux as shown by lines 1440. Magnetic flux 1440 canattract primary annular alignment component 1318 and secondary annularalignment component 1216 into alignment such that the respective centersof primary annular alignment component 1318 and secondary annularalignment component 1216 are aligned along a common axis. Sincetransmitter coil 1416 is fixed in a position concentric with primaryalignment component 1316 and receiver coil 1410 is fixed in positionconcentric with secondary alignment component 1218, a result of aligningprimary annular alignment component 1318 and secondary annular alignmentcomponent 1216 along a common axis is that transmitter coil 1416 andreceiver coil 1410 are also aligned along a common axis, therebyenabling efficient wireless power transfer. For instance, transmittercoil 1416 can be driven with an alternating current to generatetime-varying magnetic fields that induce a time-varying current inreceiver coil 1416. Electromagnetic shielding (e.g., shielding 1415 and1412) can confine the AC fields to the immediate vicinity of coils 1416and 1410.

In particular, some embodiments provide a gap region 1411 betweensecondary magnet 1428 and receiver coil assembly 1210 that mayexperience low DC magnetic flux and may also experience low ACelectromagnetic fields due to electromagnetic shielding 1412 around coil1410. Similarly, some embodiments provide a gap region 1413 betweenprimary magnet 1426 and transmitter coil assembly 1312 that mayexperience low DC magnetic flux and may also experience low ACelectromagnetic fields due to electromagnetic shielding 1418 aroundtransmitter coil 1416. In some embodiments, NFC antenna coils (notshown) may be placed in gap region 1411 and/or 1413, e.g., to supportidentification of wireless charger device 1300 by portable electronicdevice 1200. Example embodiments of NFC coil 1260 are described insection 5 below. It is noted that a similar gap region may be createdwhen using a z-pole magnetic alignment system of the kind shown in FIG.2; however, a larger space between the charging coils and magnets wouldbe required.

As can be appreciated with reference to FIG. 14B, each secondaryalignment magnet 1428 of secondary alignment component 1218 can have athin axial dimension so that secondary alignment component 1218 does notrequire an increased thickness of portable electronic device 1200. Forinstance, the axial thickness of each secondary alignment magnet 1428can be less than or equal to the thickness of receiver coil assembly1210 (including coil 1410 and shielding 1412). Primary alignmentcomponent 1426 can have a thicker axial dimension, e.g., occupying allof the axial space between enclosure 1406 and top cap 1408. In someembodiments, primary alignment component 1426 can also have a radialwidth that is slightly larger than a radial width of secondary alignmentcomponent 1428.

FIG. 15 is a block diagram illustrating an exemplary wireless chargingsystem 1500 including a portable electronic device 1504 (which can be,e.g., portable electronic device 1200 or any other portable electronicdevice described herein) and a wireless charger device 1502 (which canbe, e.g., wireless charger device 1300 or any other wireless chargerdevice described herein) that can be aligned together via a magneticalignment system 1506 according to some embodiments. Magnetic alignmentsystem 1506 can include a primary alignment component 1516 withinwireless charger device 1502 and a secondary alignment component 1518within portable electronic device 1504. Primary alignment component 1516and secondary alignment component 1516 can be constructed according toany of the embodiments described herein. Portable electronic device 1504can also include a computing system 1541 coupled to a memory bank 1542.Computing system 1541 can include control circuitry configured toexecute instructions stored in memory bank 1542 for performing variousfunctions for operating portable electronic device 1504. The controlcircuitry can include one or more programmable integrated logiccircuits, such as microprocessors, central processing units (CPUs),graphics processing units (GPUs), field programmable gate arrays(FPGAs), or the like.

Computing system 1541 can also be coupled to a user interface system1543, a communication system 1544, and a sensor system 1545 for enablingportable electronic device 1504 to perform one or more functions. Forinstance, user interface system 1543 can include a display, speaker,microphone, actuator for enabling haptic feedback, and one or more inputdevices such as a button, switch, capacitive screen for enabling thedisplay to be touch sensitive, and the like. Communication system 1544can include wireless telecommunication components, NFC components,Bluetooth components, and/or Wi-Fi components for enabling portableelectronic device 1504 to make phone calls, interact with wirelessaccessories, and access the Internet. In some embodiments, communicationsystem 1544 can include NFC reader circuitry that is used in connectionwith magnetic alignment system 1506 to identify an aligned device;examples are described in section 5 below. Sensor system 1545 caninclude light sensors, accelerometers, gyroscopes, temperature sensors,magnetometers, and/or any other type of sensor that can measure aparameter of an external entity and/or environment.

All of these electrical components require a power source to operate.Accordingly, portable electronic device 1504 also includes a battery1546 that can discharge stored energy to power the electrical componentsof portable electronic device 1504. To replenish the energy dischargedto power the electrical components, portable electronic device 1504includes charging circuitry 1547 and an inductive coil 1510 that canreceive power from wireless charger device 1502 coupled to an externalpower source 1522.

Wireless charger device 1502 can include a transmitter coil 1512 forgenerating time-varying magnetic flux capable of inducing an electricalcurrent in coil 1510 of portable electronic device 1504. The inducedcurrent can be used by charging circuitry 1547 to charge battery 1546.Wireless charger device 1502 can further include a computing system 1521coupled to a communication system 1524 and wireless charging circuitry1523. Wireless charging circuitry can include circuit components toconvert standard AC power having a first set of voltage and frequencycharacteristics (e.g., standard AC wall power) to AC power suitable foroperating coil 1510. Suitable circuit components, including rectifiers(AC-to-DC converters), boost circuits (DC-to-DC voltage boostingcircuits), inverters (DC-to-AC converters), and the like, are known inthe art. Computing system 1521 can include logic circuitry (such as amicroprocessor, microcontroller, FPGA, or the like) configured tocontrol the operation of wireless charger device 1502, such as tocontrol wireless charging circuitry 1523 to use power received fromexternal power source 1522 to generate time-varying magnetic flux toinduce current in coil 1510 to charge portable electronic device 1504.In some embodiments, computing system 1521 can implement functionalityconfirming to the Qi standard for wireless charging (promulgated by theWireless Power Consortium).

In some embodiments, components implementing computing system 1521 andwireless charging circuitry 1523 can be disposed within the housing thatholds coil 1512 and primary alignment component 1516 (e.g., withinpuck-shaped housing 1302 of FIGS. 13 and 14A-14B). In other embodiments,some or all of the components implementing computing system 1521 andwireless charging circuitry 1523 can be disposed elsewhere, e.g., at thedistal end of cable 1304 in FIGS. 13 and 14A. For example, the logiccircuitry implementing computing system 1521 can be disposed withinhousing 1302 while wireless charging circuitry 1532 is disposed in aboot of a plug connector at the distal end of cable 1304. (In this case,cable 1304 can provide AC power to wireless charger device 1300.) Asanother example, the logic circuitry implementing computing system 1521and circuit components implementing portions of wireless chargingcircuitry 1523 can be disposed within housing 1302 while circuitcomponents implementing other portions of wireless charging circuitry1523 are disposed in a boot of a plug connector at the distal end ofcable 1304. For instance, an inverter may be disposed within housing1302 while a rectifier and boost circuit are disposed in the boot. (Inthis case, cable 1304 can provide DC power to wireless charger device1300.)

While system 1500 is described with reference to particular blocks, itis to be understood that these blocks are defined for convenience ofdescription and are not intended to imply a particular physicalarrangement of component parts. The blocks need not correspond tophysically distinct components, and the same physical components can beused to implement aspects of multiple blocks. Blocks can be configuredto perform various operations, e.g., by programming a processor orproviding appropriate control circuitry, and various blocks might ormight not be reconfigurable depending on how the initial configurationis obtained. Embodiments of the present invention can be realized in avariety of apparatus including electronic devices that use using anycombination of circuitry and software to enable wireless chargingoperations and/or other operations where physical alignment betweendevices is desired.

2. Rotational Alignment Components

In various embodiments described above, a magnetic alignment system canprovide robust alignment in a lateral plane and may or may not providerotational alignment. For example, radially symmetric magnetic alignmentsystem 500 of FIGS. 5A-5B may not define a preferred rotationalorientation. Radially alternating magnetic alignment system 800 of FIGS.8A-8C can define multiple equally preferred rotational orientations. Forsome applications, such as alignment of a portable electronic devicewith a wireless charger puck or mat, rotational orientation may not be aconcern. In other applications, such as alignment of a portableelectronic device in a docking station or other mounting accessory, aparticular rotational alignment may be desirable. Accordingly, in someembodiments an annular magnetic alignment component can be augmentedwith one or more rotational alignment components positioned outboard ofand spaced apart from the annular magnetic alignment components. Therotational alignment component(s) can help guide devices into a targetrotational orientation relative to each other.

FIG. 16 shows an example of a magnetic alignment system with an annularalignment component and a rotational alignment component according tosome embodiments. FIG. 16 shows respective proximal surfaces of aportable electronic device 1604 and an accessory 1602. In this example,primary alignment components of the magnetic alignment system areincluded in an accessory device 1602, and secondary alignment componentsof the magnetic alignment system are included in a portable electronicdevice 1604. Portable electronic device 1604 can be, for example, asmart phone whose front surface provides a touchscreen display and whoseback surface is designed to support wireless charging. Accessory device1602 can be, for example, a charging dock that supports portableelectronic device 1604 such that its display is visible and accessibleto a user. For instance, accessory device 1602 can support portableelectronic device 1604 such that the display is vertical or at aconveniently tilted angle for viewing and/or touching. In the exampleshown, accessory device 1602 supports portable electronic device 1604 ina “portrait” orientation (shorter sides of the display at the top andbottom); however, in some embodiments accessory device 1602 can supportportable electronic device 1604 in a “landscape” orientation (longersides of the display at the top and bottom). Accessory device 1602 canalso be mounted on a swivel, gimbal, or the like, allowing the user toadjust the orientation of portable electronic device 1604 by adjustingthe orientation of accessory device 1602.

As described above, components of a magnetic alignment system caninclude a primary annular alignment component 1616 disposed in accessory1602 and a secondary annular alignment component 1618 disposed inportable electronic device 1604. Primary annular alignment component1616 can be similar or identical to any of the primary alignmentcomponents described above. For example, primary annular alignmentcomponent 1616 can be formed of arcuate magnets 1626 arranged in anannular configuration. Although not shown in FIG. 16, one or more gapscan be provided in primary annular alignment component 1616, e.g., byomitting one or more of arcuate magnets 1626 or by providing a gap atone or more interfaces 1630 between adjacent arcuate magnets 1626. Insome embodiments, each arcuate magnet 1626 can include an inner arcuateregion having a first magnetic orientation (e.g., axially oriented in afirst direction), an outer arcuate region having a second magneticorientation opposite the first magnetic orientation (e.g., axiallyoriented opposite the first direction), and a central non-magnetizedarcuate region between the inner and outer regions (as described above,the non-magnetized central region can include an air gap or anonmagnetic material). In some embodiments, primary annular alignmentcomponent 1616 can also include a DC shield (not shown) on the distalside of arcuate magnets 1626.

Likewise, secondary annular alignment component 1618 can be similar oridentical to any of the secondary alignment components described above.For example, secondary annular alignment component 1618 can be formed ofarcuate magnets 1628 arranged in an annular configuration. Although notshown in FIG. 16, one or more gaps can be provided in secondary annularalignment component 1618, e.g., by omitting one or more arcuate magnets1628 or by providing a gap at one or more interfaces 1632 betweenadjacent magnets 1628. As described above, arcuate magnets 1628 canprovide radially-oriented magnetic polarities. For instance, all sectorsof secondary annular alignment component 1618 can have aradially-outward magnetic orientation or a radially-inward magneticorientation, or some sectors of secondary annular alignment component1618 may have a radially-outward magnetic orientation while othersectors of secondary annular alignment component 1618 have aradially-inward magnetic orientation.

As described above, primary annular alignment component 1616 andsecondary annular alignment component 1618 can provide shear forces thatpromote alignment in the lateral plane so that center point 1601 ofprimary annular alignment component 1616 aligns with center point 1603of secondary annular alignment component 1618. However, primary annularalignment component 1616 and secondary annular alignment component 1618might not provide torque forces that favor any particular rotationalorientation, such as portrait orientation.

Accordingly, in some embodiments, a magnetic alignment system canincorporate one or more rotational alignment components in addition tothe annular alignment components. The rotational alignment componentscan include one or more magnets that provide torque about the commonaxis of the (aligned) annular alignment components, so that a preferredrotational orientation can be reliably established. For example, asshown in FIG. 16, a primary rotational alignment component 1622 can bedisposed outboard of and spaced apart from primary annular alignmentcomponent 1616 while a secondary rotational alignment component 1624 isdisposed outboard of and spaced apart from secondary annular alignmentcomponent 1618. Secondary rotational alignment component 1624 can bepositioned at a fixed distance (y₀) from center point 1603 of secondaryannular alignment component 1618 and centered between the side edges ofportable electronic device 1604 (as indicated by distance x₀ from eitherside edge). Similarly, primary rotational alignment component 1622 canbe positioned at the same distance y₀ from center point 1601 of primaryannular alignment component 1616 and located at a rotational angle thatresults in a torque profile that favors the desired orientation ofportable electronic device 1604 relative to accessory 1602 whensecondary rotational alignment component 1624 is aligned with primaryrotational alignment component 1622. It should be noted that the samedistance y₀ can be applied in a variety of portable electronic deviceshaving different form factors, so that a single accessory can becompatible with a family of portable electronic devices. A longerdistance y₀ can increase torque toward the preferred rotationalalignment; however, the maximum distance y₀ may be limited by designconsiderations, such as the size of the smallest portable electronicdevice in a family of portable electronic devices that incorporatemutually compatible magnetic alignment systems.

According to some embodiments, each of primary rotational alignmentcomponent 1622 and secondary rotational alignment component 1624 can beimplemented using one or more magnets (e.g., rare earth magnets such asNdFeB) each of which has each been magnetized such that its magneticpolarity is oriented in a desired direction. In the example of FIG. 16,the magnets have rectangular shapes; however, other shapes (e.g.,rounded shapes) can be substituted. The magnetic orientations ofrotational alignment components 1622 and 1624 can be complementary sothat when the proximal surfaces of rotational alignment components 1622and 1624 are near each other, an attractive magnetic force is exerted.This attractive magnetic force can help to rotate portable electronicdevice 1604 and accessory 1602 into a preferred rotational orientationin which the proximal surfaces of rotational alignment components 1622and 1624 are aligned with each other. Examples of magnetic orientationsfor rotational alignment components 1622 and 1624 that can be used toprovide a desired attractive force are described below. In someembodiments, primary rotational alignment component 1622 and secondaryrotational alignment component 1624 can have the same lateral (xy)dimensions and the same thickness. The dimensions can be chosen based ona desired magnetic field strength and/or torque, the dimensions ofdevices in which the rotational alignment components are to be deployed,and other design considerations. In some embodiments, the lateraldimensions can be about 6 mm (x direction) by about 16 mm (y direction),and the thickness can be anywhere from about 0.3 mm to about 1.5 mm; theparticular dimensions can be chosen based on the sizes of the devicesthat are to be aligned. In some embodiments, the thickness of therotational alignment component for a given device can be chosen to matchthe thickness of an annular alignment component in that device. In someembodiments, each of primary rotational alignment component 1622 andsecondary rotational alignment component 1624 can be implemented usingtwo or more rectangular blocks of magnetic material positioned adjacentto each other. As in other embodiments, a small gap may be presentbetween adjacent magnets, e.g., due to manufacturing tolerances.

FIGS. 17A and 17B show an example of rotational alignment according tosome embodiments. In FIG. 17A, accessory 1602 is placed on the backsurface of portable electronic device 1604 such that primary annularalignment component 1616 and secondary alignment component 1618 arealigned with each other in the lateral plane such that, in the viewshown, center point 1601 of primary annular alignment component 1616overlies center point 1603 of secondary annular alignment component1618. A relative rotation is present such that rotational alignmentcomponents 1622 and 1624 are not aligned. In this configuration, anattractive force between rotational alignment components 1622 and 1624can urge portable electronic device 1604 and accessory 1602 toward atarget rotational orientation. In FIG. 17B, the attractive magneticforce between rotational alignment components 1622 and 1624 has broughtportable electronic device 1604 and accessory 1602 into the targetrotational alignment with the sides of portable electronic device 1604parallel to the sides of accessory 1602. In some embodiments, theattractive magnetic force between rotational alignment components 1622and 1624 can also help to hold portable electronic device 1604 andaccessory 1602 in a fixed rotational alignment.

Rotational alignment components 1622 and 1624 can have various patternsof magnetic orientations. As long as the magnetic orientations ofrotational alignment components 1622 and 1624 are complementary to eachother, a torque toward the target rotational orientation can be presentwhen the devices are brought into lateral alignment and close to thetarget rotational orientation. FIGS. 18A-21B show examples of magneticorientations for a rotational alignment component according to variousembodiments. While the magnetic orientation is shown for only onerotational alignment component, it should be understood that themagnetic orientation of a complementary rotational alignment componentcan be complementary to the magnetic orientation of shown.

FIGS. 18A and 18B show a perspective view and a top view of a rotationalalignment component 1824 having a “z-pole” configuration according tosome embodiments. It should be understood that the perspective view isnot to any particular scale and that the lateral (xy) dimensions andaxial (z) thickness can be varied as desired. As shown in FIG. 18A,rotational alignment component 1824 can have a uniform magneticorientation along the axial direction, as indicated by arrows 1805.Accordingly, as shown in FIG. 18B, a north magnetic pole (N) may benearest the proximal surface 1803 of rotational alignment component1824. A complementary z-pole alignment component can have a uniformmagnetic orientation with a south magnetic pole nearest the proximalsurface. The z-pole configuration can provide reliable alignment.

Other configurations can provide reliable alignment as well as astronger, or more salient, “clocking” sensation for the user. A“clocking sensation,” in this context, refers to a user-perceptibletorque about the common axis of the annular alignment components thaturges toward the target rotational alignment and/or resists smalldisplacements from the target rotational alignment. A greater variationof torque as a function of rotational angle can provide a more salientclocking sensation. Following are examples of magnetizationconfigurations for a rotational alignment component that can providemore salient clocking sensations than the z-pole configuration of FIGS.18A and 18B.

FIGS. 19A and 19B show a perspective view and a top view of a rotationalalignment component 1924 having a “quad-pole” configuration according tosome embodiments. It should be understood that the perspective view isnot to any particular scale and that the lateral (xy) dimensions andaxial (z) thickness can be varied as desired. As shown in FIG. 19A,rotational alignment component 1924 has a first magnetized region 1925with a magnetic orientation along the axial direction such that thenorth magnetic pole (N) is nearest the proximal (+z) surface 1903 ofrotational alignment component 1924 (as indicated by arrow 1905) and asecond magnetized region 1927 with a magnetic orientation opposite tothe magnetic orientation of the first region such that the southmagnetic pole (S) is nearest to proximal surface 1903 (as indicated byarrows 1907). Between magnetized regions 1925 and 1927 is a centralregion 1929 that is not magnetized. In some embodiments, rotationalalignment component 1924 can be formed from a single piece of magneticmaterial that is exposed to a magnetizer to create regions 1925, 1927,1929. Alternatively, rotational alignment component 1924 can be formedusing two pieces of magnetic material with a nonmagnetic material or anair gap between them. As shown in FIG. 19B, the proximal surface ofrotational alignment component 1924 can have one region having a “north”polarity and another region having a “south” polarity. A complementaryquad-pole rotational alignment component can have corresponding regionsof south and north polarity at the proximal surface.

FIGS. 20A and 20B show a perspective view and a top view of a rotationalalignment component 2024 having an “annulus design” configurationaccording to some embodiments. It should be understood that theperspective view is not to any particular scale and that the lateral(xy) dimensions and axial (z) thickness can be varied as desired. Asshown in FIG. 20A, rotational alignment component 2024 has an annularouter magnetized region 2025 with a magnetic orientation along the axialdirection such that the north magnetic pole (N) is nearest the proximal(+z) surface 2003 of rotational alignment component 2024 (as shown byarrows 2005) and an inner magnetized region 2027 with a magneticorientation opposite to the magnetic orientation of the first regionsuch that the south magnetic pole (S) is nearest to proximal surface2003. Between magnetized regions 2025 and 2027 is a neutral annularregion 2029 that is not magnetized. In some embodiments, rotationalalignment component 2024 can be formed from a single piece of magneticmaterial that is exposed to a magnetizer to create regions 2025, 2027,2029. Alternatively, rotational alignment component 2024 can be formedusing two or more pieces of magnetic material with a nonmagneticmaterial or an air gap between them. As shown in FIG. 20B, the proximalsurface of rotational alignment component 2024 can have an annular outerregion having a “north” polarity and an inner region having a “south”polarity. The proximal surface of a complementary annulus-designrotational alignment component can have an annular outer region of southpolarity and an inner region of north polarity.

FIGS. 21A and 21B show a perspective view and a top view of a rotationalalignment component 2124 having a “triple pole” configuration accordingto some embodiments. It should be understood that the perspective viewis not to any particular scale and that the lateral (xy) dimensions andaxial (z) thickness can be varied as desired. As shown in FIG. 21A,rotational alignment component 2124 has a central magnetized region 2125with a magnetic orientation along the axial direction such that thesouth magnetic pole (S) is nearest the proximal (+z) surface 2103 ofrotational alignment component 2124 (as shown by arrow 2105) and outermagnetized regions 2127, 2129 with a magnetic orientation opposite tothe magnetic orientation of central region 2125 such that the northmagnetic pole (N) is nearest to proximal surface 2103 (as shown byarrows 2107, 2109). Between central magnetized region 2125 and each ofouter magnetized regions 2127, 2129 is a neutral region 2131, 2133 thatis not strongly magnetized. In some embodiments, rotational alignmentcomponent 2124 can be formed from a single piece of magnetic materialthat is exposed to a magnetizer to create regions 2125, 2127, 2129.Alternatively, rotational alignment component 2124 can be formed usingthree (or more) pieces of magnetic material with nonmagnetic materialsor air gaps between them. As shown in FIG. 21B, the proximal surface mayhave a central region having a “south” polarity with an outer regionhaving “north” polarity to either side. The proximal surface of acomplementary triple-pole rotational alignment component can have acentral region of north polarity with an outer region of south polarityto either side.

It should be understood that the examples in FIGS. 18A-21B areillustrative and that other configurations may be used. The selection ofa magnetization pattern for a rotational alignment component can beindependent of the magnetization pattern of an annular alignmentcomponent with which the rotational alignment component is used.

In some embodiments, the selection of a magnetization pattern for arotational alignment component can be based on optimizing the torqueprofile. For example, as noted above, it may be desirable to provide asalient clocking sensation to a user when close to the desiredrotational alignment. The clocking sensation can be a result of torqueabout a rotational axis defined by the annular alignment components. Theamount of torque depends on various factors, including the distancebetween the axis and the rotational alignment component (distance y0 inFIG. 16) and the length (in the y direction as defined in FIG. 16) ofthe rotational alignment component, as well as the strength of themagnetic fields of the rotational alignment components (which may dependon the size of the rotational alignment components), the coefficient offriction between the surfaces being aligned, and whether the annularalignment components exert any torque toward a preferred rotationalorientation.

FIG. 22 shows a graph of torque as a function of angular rotation (indegrees) for an alignment system of the kind shown in FIG. 16, fordifferent magnetization configurations of the rotational alignmentcomponent according to various embodiments. Angular rotation is definedsuch that zero degrees corresponds to the target rotational alignment(where the proximal surfaces of rotational angular components 1622 and1624 are in closest proximity, e.g., as shown in FIG. 17B). Torque isdefined such that positive (negative) values indicate force in thedirection of decreasing (increasing) rotational angle. For purpose ofgenerating the torque profiles, it is assumed that annular alignmentcomponents 1616 and 1618 are rotationally symmetric and do not exerttorque about the z axis defined by center points 1601 and 1603. Threedifferent magnetization configurations are considered. Line 2204corresponds to the quad-pole configuration of FIGS. 19A and 19B. Line2205 corresponds to the annulus design configuration of FIGS. 20A and20B. Line 2206 corresponds to the triple-pole configuration of FIGS. 21Aand 21B. As shown, the annulus design (line 2205) and triple-pole (line2206) configurations provide a sharper peak in the torque and thereforea more salient clocking sensation for the user, as compared to thequad-pole configuration (line 2204). In addition, the triple-poleconfiguration provides a stronger peak torque and therefore a moresalient clocking sensation than the annulus-design configuration. (Thetriple-pole configuration can also provide reduced flux leakage ascompared to other configurations.) It should be understood that thenumerical values in FIG. 22 are illustrative, and that torque in aparticular embodiment may depend on a variety of other factors inaddition to the magnetization configuration, such as the magnet volume,aspect ratio, and distance y0 from the center of the annular alignmentcomponent.

In the example shown in FIG. 16, a single rotational alignment componentis placed outboard of the annular alignment component at a distance y₀from the center of the annular alignment component. This arrangementallows a single magnetic element to generate torque that produces asalient clocking sensation for a user aligning devices. In someembodiments, other arrangements are also possible. For example, FIG. 23shows a portable electronic device 2304 having an alignment system 2300with multiple rotational alignment components according to someembodiments. In this example, alignment system 2300 includes an annularalignment component 2318 and a set of rotational alignment components2324 positioned at various locations around the perimeter of annularalignment component 2318. In this example, there are four rotationalalignment components 2324 positioned at angular intervals ofapproximately 90 degrees. In other embodiments, different numbers andspacing of rotational alignment components can be used. Each rotationalalignment component 2324 can have any of the magnetizationconfigurations described above, including z-pole, quad-pole,triple-pole, or annulus-design configurations, or a differentconfiguration. Further, different rotational alignment components 2324can have different magnetization configurations from each other. Itshould be noted that rotational alignment components 2324 can be placedclose to the perimeter of annular alignment component 2318, and thelarger number of magnetic components can provide sufficient torque witha shorter lever arm. Complementary rotational alignment components canbe disposed around the outer perimeter of any type of annular alignmentcomponent (e.g., primary alignment components, secondary alignmentcomponents, or annular alignment components as described herein).

It will be appreciated that the foregoing examples of rotationalalignment components are illustrative and that variations ormodifications are possible. In some embodiments, a rotational alignmentcomponent can be provided as an optional adjunct to an annular alignmentcomponent, and a device that has both an annular alignment component anda rotational alignment component can align laterally to any other devicethat has a complementary annular alignment component, regardless ofwhether the other device has or does not have a rotational alignmentcomponent. Thus, for example, portable electronic device 1604 of FIG. 16can align rotationally to accessory 1602 (which has both annularalignment component 1616 and rotational alignment component 1622) aswell as aligning laterally to another accessory (such as wirelesscharger device 400 of FIG. 4) that has annular alignment component 1616but not rotational alignment component 1622. In the latter case, lateralalignment can be achieved, e.g., to support efficient wireless charging,but there may be no preferred rotational alignment, or rotationalalignment may be achieved using a nonmagnetic feature (e.g., amechanical retention feature such as a ledge, a clip, a notch, or thelike). A rotational magnetic alignment component can be used togetherwith any type of annular magnetic alignment component (e.g., primaryannular magnetic alignment components, secondary annular magneticalignment components, or auxiliary annular magnetic alignment componentsas described below).

3. Primary, Secondary, and Auxiliary Annular Magnetic AlignmentComponents

3.1. Overview of Three-Component Magnetic Alignment Systems

In some embodiments, a magnetic alignment system can align more than twodevices. Examples of magnetic alignment systems with three annularalignment components (referred to as primary, secondary, and auxiliaryannular magnetic alignment components) will now be described. It shouldbe understood that the primary and secondary annular magnetic alignmentcomponents described in this section can be identical to primary andsecondary annular magnetic alignment components described above and thata given pair primary and secondary annular magnetic alignment componentscan be used with or without an auxiliary annular magnetic alignmentcomponent. It should also be understood that a system where alignment isdesired may include more than three devices and that additionalauxiliary annular alignment components can be provided to facilitatealignment of more than three devices.

FIG. 24 shows a simplified representation of a wireless charging system2400 incorporating a three-component magnetic alignment system 2406according to some embodiments. Wireless charging system 2400 includes aportable electronic device 2404, a wireless charger device 2402, and anaccessory 2420 positioned between portable electronic device 2404 andwireless charger device 2402. Portable electronic device 2404 can be aconsumer electronic device, such as a smart phone, tablet, wearabledevice, or the like, or any other electronic device for which wirelesscharging is desired. Wireless charger device 2402 can be any device thatis configured to generate time-varying magnetic flux to induce a currentin a suitably configured receiving device. For instance, wirelesscharger device 2402 can be a wireless charging mat, puck, dockingstation, or the like. Wireless charger device 2402 can include or haveaccess to a power source such as battery power or standard AC power.

To enable wireless power transfer, portable electronic device 2404 andwireless charger device 2402 can include inductive coils 2410 and 2412,respectively, which can operate to transfer power between them. Forexample, inductive coil 2412 can be a transmitter coil that generates atime-varying magnetic flux 2414, and inductive coil 2410 can be areceiver coil in which an electric current is induced in response totime-varying magnetic flux 2414. The received electric current can beused to charge a battery of portable electronic device 2404, to provideoperating power to a component of portable electronic device 2404,and/or for other purposes as desired. In some embodiments, wirelesspower transfer between wireless charger device 2402 and portableelectronic device 2404 can occur regardless of whether accessory 2420 ispresent.

Accessory 2420 can be an accessory that is used with portable electronicdevice 2404 to protect, enhance, and/or supplement the aesthetics and/orfunctions of portable electronic device 2404. For example, accessory2420 can be a protective case, an external battery pack, a cameraattachment, or any other charge-through accessory. In some embodiments,accessory 2420 can include one or more wireless charging coils 2438. Forexample, accessory 2420 can be a portable external battery pack that canbe attached to and carried together with portable electronic device2404. In some embodiments, accessory 2420 can operate wireless chargingcoil 2438 as a receiver coil to charge its onboard battery (e.g., fromwireless charger device 2402) or as a transmitter coil to provide powerto portable electronic device 2404. In some embodiments, accessory 2420cam include separate transmitter and receiver coils 2438. Accessory 2420can operate coil(s) 2438 to transmit power or to receive and store powerdepending on current conditions. In still other embodiments, accessory2420 can be an “unpowered” or “passive” accessory such as a case thatcontains no active circuitry, and wireless charging coil 2438 can beomitted. In such cases, accessory 2420 can be designed not to inhibitwireless power transfer between wireless charger device 2402 andportable electronic device 2404. For instance, relevant portions ofaccessory 2420 can be made of a material such as plastic, leather, orother material that is transparent to time-varying magnetic flux 2414.

To enable efficient wireless power transfer, it is desirable to aligninductive coils 2412 and 2410 (and coil 2438 in embodiments where coil2438 is present). According to some embodiments, magnetic alignmentsystem 2406 can provide such alignment. In the example shown in FIG. 24,magnetic alignment system 2406 includes a primary magnetic alignmentcomponent 2416 disposed within or on a surface of wireless chargerdevice 2402, a secondary magnetic alignment component 2418 disposedwithin or on a surface of portable electronic device 2402, and anauxiliary magnetic alignment component 2470 disposed within or on asurface of accessory 2420. Primary, secondary, and auxiliary magneticalignment components 2416, 2418, and 2470 are configured to magneticallyattract one another into an aligned position in which inductive coils2410 and 2412 (and/or 2438 if present) are aligned with one another toprovide efficient wireless power transfer.

Magnetic alignment system 2406 can enable modularity in that varioustypes of accessories 2420 can align with primary and/or secondarymagnetic alignment components 2416, 2418, provided that accessory 2420includes auxiliary alignment component 2470. For instance, in someembodiments (e.g., where accessory 2420 is a protective case), accessory2420 can mechanically couple to portable electronic device 2404 in afixed position such that auxiliary magnetic alignment component 2470 isaligned with secondary magnetic alignment component 2418, and portableelectronic device 2404 can rely wholly or partially on auxiliarymagnetic alignment component 2470 to align with primary alignmentcomponent 2418 of wireless charger device 2402. Accordingly, whenaccessory 2420 is positioned on charging surface 2408 of wirelesscharger device 2402 such that primary alignment component 2416 isaligned with auxiliary alignment component 2470, secondary alignmentcomponent 2418 of portable electronic device 2404 is also aligned withprimary alignment component 2416, and efficient wireless power transferis supported.

As another example, in some embodiments where accessory 2420 is anexternal battery, auxiliary alignment component 2470 can attract to andalign with secondary alignment component 2418 so that power from aninternal power source (not shown) within accessory 2420 can bewirelessly transferred to portable electronic device 2404 usinginductive coil 2438 and inductive coil 2410. The modularity of magneticalignment system 2406 can also enable wireless charger device 2402 tostack with portable electronic device 2404 and accessory 2420. Forexample, auxiliary alignment component 2470 can attract and align tosecondary alignment component 2418 and at the same time can attract andalign to primary alignment component 2416. Accordingly, when portableelectronic device 2404, accessory 2420, and wireless charger device 2402are all stacked together, power can be transmitted wirelessly fromwireless charger device 2402 to accessory 2420 (e.g., to charge aninternal battery of accessory 2420) and from accessory 2420 to portableelectronic device 2404. Both power transfers can be performedsimultaneously; i.e., wireless charger device 2402 can provide power toaccessory 2420 at the same time that accessory 2420 provides power toportable electronic device 2404. In some embodiments, to enablesimultaneous power transfers, accessory 2420 can include two inductivecoils 2438, one for receiving power and one for transmitting power. Inother embodiments, the power transfers can be performed sequentially;e.g., wireless charger device 2402 can provide power to accessory 2420,and at a time when wireless charger device 2402 is not providing power,accessory 2420 can provide power to portable electronic device 2404.

FIG. 24 is illustrative and not limiting. For example, while FIG. 24shows three devices stacked together, it should be understood that thesame principles can be applied to form systems of four or more devices.For instance, a wireless charging system can include a portableelectronic device coupled to a protective case that is attached to andmagnetically aligned with an external battery, which is attached to andmagnetically aligned to a wireless charger device. All the inductivecoils within the respective devices can be aligned together, andwireless power can be transmitted between the wireless charger deviceand the external battery, between the battery and the portableelectronic device, and/or between the wireless charger device and theportable electronic device. It is to be appreciated that any number ofdevices can be stacked together without departing from the spirit andscope of the present disclosure.

According to embodiments described herein, an alignment component(including a primary, secondary, or auxiliary alignment component) of amagnetic alignment system can be formed of arcuate magnets arranged inan annular configuration. In some embodiments, each magnet can have itsmagnetic polarity oriented in a desired direction so that magneticattraction between the primary, secondary, and auxiliary alignmentcomponents provides a desired alignment. In some embodiments, an arcuatemagnet can include a first magnetic region with magnetic polarityoriented in a first direction and a second magnetic region with magneticpolarity oriented in a second direction different from the firstdirection. As will be described, different configurations can providedifferent degrees of magnetic field leakage.

3.2. Magnetic Alignment Systems with a Single Axial Magnetic Orientation

FIG. 25A shows a perspective view of a magnetic alignment system 2500according to some embodiments, and FIG. 25B shows a cross-sectionthrough magnetic alignment system 2500 across the cut plane indicated inFIG. 25A. Magnetic alignment system 2500 can be an implementation ofmagnetic alignment system 2406 of FIG. 24. In magnetic alignment system2500, the alignment components all have magnetic polarity oriented inthe same direction (along the axis of the annular configuration).

As shown in FIG. 25A, magnetic alignment system 2500 can include aprimary alignment component 2516 (which can be an implementation ofprimary alignment component 2416 of FIG. 24), a secondary alignmentcomponent 2518 (which can be an implementation of secondary alignmentcomponent 2418 of FIG. 24), and an auxiliary alignment component 2570(which can be an implementation of auxiliary alignment component 2470described above). Primary alignment component 2516, secondary alignmentcomponent 2518, and auxiliary alignment component 2570 have annularshapes and may also be referred to as “annular” alignment components.The particular dimensions can be chosen as desired. In some embodiments,the dimensions can be similar to example values given above in section1.

Primary alignment component 2516 can include a number of sectors, eachof which can be formed of one or more primary arcuate magnets 2526.Secondary alignment component 2518 can include a number of sectors, eachof which can be formed of one or more secondary arcuate magnets 2528.Auxiliary alignment component 2470 can include a number of sectors, eachof which can be formed of one or more auxiliary arcuate magnets 2572. Inthe example shown, the number of primary magnets 2526 is equal to thenumber of secondary magnets 2528 and to the number of auxiliary magnets2572, and each sector includes exactly one magnet, but this is notrequired. Primary magnets 2526, secondary magnets 2528, and auxiliarymagnets 2572 can have arcuate (or curved) shapes in the transverse planesuch that when primary magnets 2526 (or secondary magnets 2528 orauxiliary magnets 2572) are positioned adjacent to one anotherend-to-end, primary magnets 2526 (or secondary magnets 2528 or auxiliarymagnets 2572) form an annular structure as shown. In some embodiments,primary magnets 2526 can be in contact with each other at interfaces2530, secondary magnets 2528 can be in contact with each other atinterfaces 2532, and auxiliary magnets 2572 can be in contact with eachother at interfaces 2574. Alternatively, small gaps or spaces mayseparate adjacent primary magnets 2526 or adjacent secondary magnets2528 or adjacent auxiliary magnets 2572, providing a greater degree oftolerance during manufacturing.

In some embodiments, primary alignment component 2516 can also includean annular shield 2514 disposed on a distal surface of primary magnets2526. In some embodiments, shield 2514 can be formed as a single annularpiece of material and adhered to primary magnets 2526 to secure primarymagnets 2526 into position. Shield 2514 can be formed of a material thathas high magnetic permeability and/or high magnetic saturation value,such as stainless steel or low-carbon steel, and can redirect magneticfields to prevent them from propagating beyond the distal side ofprimary alignment component 2516, thereby protecting sensitiveelectronic components located beyond the distal side of primaryalignment component 2516 from magnetic interference.

Primary magnets 2526, secondary magnets 2528, and auxiliary magnets 2572can be made of a magnetic material such as an NdFeB material, other rareearth magnetic materials, or other materials that can be magnetized tocreate a persistent magnetic field. Each primary magnet 2526, eachsecondary magnet 2528, and each auxiliary magnet 2572 can have amonolithic structure having a single magnetic region with a magneticpolarity aligned in the axial direction as shown by magnetic polarityindicators 2515, 2517, 2519 in FIG. 25B. For example, each primarymagnet 2526, each secondary magnet 2528, and each auxiliary magnet 2572can be a bar magnet that has been ground and shaped into an arcuatestructure having an axial magnetic orientation. In the example shown,primary magnet 2526 has its north pole oriented toward the proximalsurface and south pole oriented toward the distal surface, secondarymagnet 2528 has its south pole oriented toward the proximal surface andnorth pole oriented toward the distal surface, and auxiliary magnet 2572has a corresponding magnetic orientation such that the north pole ofauxiliary magnet 2572 is oriented toward the proximal surface ofsecondary magnet 2528 and the south pole of auxiliary magnet 2572 isoriented toward the proximal surface of primary magnet 2526. In otherembodiments, the magnetic orientations can be reversed such that primarymagnet 2526 has its south pole oriented toward the proximal surface andnorth pole oriented toward the distal surface while secondary magnet2528 has its north pole oriented toward the proximal surface and southpole oriented toward the distal surface and auxiliary magnet 2572 has acorresponding magnetic orientation such that the south pole of auxiliarymagnet 2572 is oriented toward the proximal surface of secondary magnet2528 and the north pole of auxiliary magnet 2572 is oriented toward theproximal surface of primary magnet 2526.

As shown in FIG. 25B, the axial magnetic orientations of primary magnet2526, auxiliary magnet 2572, and secondary magnet 2528 can generatemagnetic fields 2540 that exert attractive forces between primary magnet2526 and auxiliary magnet 2572 and between auxiliary magnet 2572 andsecondary magnet 2528, thereby facilitating alignment between respectivedevices in which primary alignment component 2516, auxiliary alignmentcomponent 2570, and secondary alignment component 2518 are disposed(e.g., as shown in FIG. 24). While shield 2514 can redirect some ofmagnetic fields 2540 away from regions below primary magnet 2526,magnetic fields 2540 may still propagate to regions laterally adjacentto primary magnet 2526 and secondary magnet 2528. In some embodiments,the lateral propagation of magnetic fields 2540 may result in magneticfield leakage to other magnetically sensitive components. For instance,if an inductive coil having a ferromagnetic shield is placed in theinterior (or inboard) region of annular primary alignment component 2516(or secondary alignment component 2518), leakage of magnetic fields 2540may saturate the ferrimagnetic shield, which can degrade wirelesscharging performance.

It will be appreciated that magnetic alignment system 2500 isillustrative and that variations and modifications are possible. Forinstance, while primary alignment component 2516, auxiliary alignmentcomponent 2570, and secondary alignment component 2518 are each shown asbeing constructed of eight arcuate magnets, other embodiments may use adifferent number of magnets, such as sixteen magnets, thirty-sixmagnets, or any other number of magnets, and the number of primarymagnets need not be equal to the number of secondary magnets. Similarly,the number of auxiliary magnets need not be equal to either the numberof primary magnets or the number of secondary magnets. In otherembodiments, primary alignment component 2516 and/or secondary alignmentcomponent 2518 and/or auxiliary alignment component 2570 can each beformed of a single, monolithic annular magnet; however, segmentingalignment components 2516, 2518, and 2570 into arcuate magnets mayimprove manufacturing, as described above with reference to FIGS. 3A and3B.

3.3. Magnetic Alignment Systems with Closed-Loop Magnetic Configurations

As noted above with reference to FIG. 25B, a magnetic alignment systemwith a single axial magnetic orientation may allow lateral leakage ofmagnetic fields, which may adversely affect performance of othercomponents of an electronic device. Accordingly, some embodimentsprovide magnetic alignment systems with a closed-loop magneticconfiguration that reduces magnetic field leakage. Examples will now bedescribed.

FIG. 26A shows a perspective view of a magnetic alignment system 2600according to some embodiments, and FIG. 26B shows a cross-sectionthrough magnetic alignment system 2600 across the cut plane indicated inFIG. 26A. Magnetic alignment system 2600 can be an implementation ofmagnetic alignment system 2406 of FIG. 24. In magnetic alignment system2600, the alignment components have magnetic components configured in a“closed loop” configuration as described below.

As shown in FIG. 26A, magnetic alignment system 2600 can include aprimary alignment component 2616 (which can be an implementation ofprimary alignment component 2416 of FIG. 24), a secondary alignmentcomponent 2618 (which can be an implementation of secondary alignmentcomponent 2418 of FIG. 24), and an auxiliary alignment component 2670(which can be an implementation of auxiliary alignment component 2470 ofFIG. 24). Primary alignment component 2616, secondary alignmentcomponent 2618, and auxiliary alignment component 2670 have annularshapes and may also be referred to as “annular” alignment components.The particular dimensions can be chosen as desired. In some embodiments,the dimensions can be similar to example values given above in section1.

Primary alignment component 2616 can include a number of sectors, eachof which can be formed of a number of primary magnets 2626; secondaryalignment component 2618 can include a number of sectors, each of whichcan be formed of a number of secondary magnets 2628; and auxiliaryalignment component 2670 can include a number of sectors, each of whichcan be formed of a number of auxiliary magnets 2672. In the exampleshown, the number of primary magnets 2626 is equal to the number ofsecondary magnets 2628 and to the number of auxiliary magnets 2672, andeach sector includes one magnet, but this is not required. Primarymagnets 2626, secondary magnets 2628, and auxiliary magnets 2672 canhave arcuate (or curved) shapes in the transverse plane such that whenprimary magnets 2626 (or secondary magnets 2628 or auxiliary magnets2672) are positioned adjacent to one another end-to-end, primary magnets2626 (or secondary magnets 2628 or auxiliary magnets 2672) form anannular structure as shown. In some embodiments, adjacent primarymagnets 2626 can be in contact with each other at interfaces 2630,adjacent secondary magnets 2628 can be in contact with each other atinterfaces 2632, and adjacent auxiliary magnets 2672 can be in contactwith each other at interfaces 2680. Alternatively, small gaps or spacesmay separate adjacent primary magnets 2626, adjacent secondary magnets2628, or adjacent auxiliary magnets 2672, providing a greater degree oftolerance during manufacturing.

In some embodiments, primary alignment component 2616 can also includean annular shield 2614 disposed on a distal surface of primary magnets2626. In some embodiments, shield 2614 can be formed as a single annularpiece of material and adhered to primary magnets 2626 to secure primarymagnets 2626 into position. Shield 2614 can be formed of a material thathas high magnetic permeability, such as stainless steel, and canredirect magnetic fields to prevent them from propagating beyond thedistal side of primary alignment component 2616, thereby protectingsensitive electronic components located beyond the distal side ofprimary alignment component 2616 from magnetic interference. In someembodiments, auxiliary alignment component 2670 does not include asimilar shield, so that a stronger magnetic attraction with primaryalignment component 2616 can be provided.

Primary magnets 2626, secondary magnets 2628, and auxiliary magnets 2672can be made of a magnetic material such as an NdFeB material, other rareearth magnetic materials, or other materials that can be magnetized tocreate a persistent magnetic field. Each secondary magnet 2628 can havea single magnetic region with a magnetic polarity having a component inthe radial direction in the transverse plane (as shown by magneticpolarity indicator 2617 in FIG. 26B). As described below, the magneticorientation can be in a radial direction with respect to axis 2601 oranother direction having a radial component in the transverse plane.Each primary magnet 2626 can include two magnetic regions havingopposite magnetic orientations. For example, each primary magnet 2626can include an inner arcuate magnetic region 2652 having a magneticorientation in a first axial direction (as shown by polarity indicator2653 in FIG. 26B), an outer arcuate magnetic region 2654 having amagnetic orientation in a second axial direction opposite the firstdirection (as shown by polarity indicator 2655 in FIG. 26B), and acentral non-magnetized region 2656 that does not have a magneticorientation. Central non-magnetized region 2656 can magneticallyseparate inner arcuate region 2652 from outer arcuate region 2654 byinhibiting magnetic fields from directly crossing through center region2656. Similarly, each auxiliary magnet 2672 can include two magneticregions having opposite magnetic orientations. For example, eachauxiliary magnet 2672 can include an inner arcuate magnetic region 2674having a magnetic orientation in a first axial direction (as shown bypolarity indicator 2673 in FIG. 26B), an outer arcuate magnetic region2676 having a magnetic orientation in a second axial direction oppositethe first direction (as shown by polarity indicator 2675 in FIG. 26B),and a central non-magnetized region 2678 that does not have a magneticorientation. Central non-magnetized region 2678 can magneticallyseparate inner arcuate region 2674 from outer arcuate region 2676 byinhibiting magnetic fields from directly crossing through center region2678.

In some embodiments, each secondary magnet 2626 can be made of amagnetic material that has been ground and shaped into an arcuatestructure, and a magnetic orientation having a radial component in thetransverse plane can be created, e.g., using a magnetizer. Similarly,each primary magnet 2626 can be made of a single piece of magneticmaterial that has been ground and shaped into an arcuate structure, anda magnetizer can be applied to the arcuate structure to induce an axialmagnetic orientation in one direction within an inner arcuate region ofthe structure and an axial magnetic orientation in the oppositedirection within an outer arcuate region of the structure, whiledemagnetizing or avoiding creation of a magnetic orientation in thecentral region. In some alternative embodiments, each primary magnet2626 can be a compound structure with two arcuate pieces of magneticmaterial providing inner arcuate magnetic region 2652 and outer arcuatemagnetic region 2654; in such embodiments, central non-magnetized region2656 can be formed of an arcuate piece of nonmagnetic material or formedas an air gap defined by sidewalls of inner arcuate magnetic region 2652and outer arcuate magnetic region 2654. Any manufacturing technique thatcan be used to form primary magnets 2626 can also be used to formauxiliary magnets 2672. Thus, each auxiliary magnet 2672 can be made ofa single piece of magnetic material that has been ground and shaped intoan arcuate structure, and a magnetizer can be applied to the arcuatestructure to induce an axial magnetic orientation in one directionwithin an inner arcuate region of the structure and an axial magneticorientation in the opposite direction within an outer arcuate region ofthe structure, while demagnetizing or avoiding creation of a magneticorientation in the central region. In some alternative embodiments, eachauxiliary magnet 2672 can be a compound structure with two arcuatepieces of magnetic material providing inner arcuate magnetic region 2674and outer arcuate magnetic region 2676; in such embodiments, centralnon-magnetized region 2678 can be formed of an arcuate piece ofnonmagnetic (or demagnetized) material or formed as an air gap definedby sidewalls of inner arcuate magnetic region 2674 and outer arcuatemagnetic region 2676. It should be understood that in some embodimentsone manufacturing technique can be used for primary magnets 2626 while adifferent manufacturing technique can be used for auxiliary magnets2672; for example, each auxiliary magnet 2672 can be monolithic whileeach primary magnet 2626 is a compound structure. As long as themagnetic fields of the various magnets align as described, alignmentbetween devices can be provided. Further, as described above withreference to FIGS. 3A and 3B, the inner and outer arcuate magneticregions of a quad-pole primary or auxiliary arcuate magnet can but neednot have equal magnetic field strength; asymmetric polarization asdescribed above can be applied.

As shown in FIG. 26B, inner arcuate magnetic region 2652 of primarymagnet 2626 and inner arcuate magnetic region 2674 of auxiliary magnet2672 can have the same magnetic orientation, as shown by polarityindictors 2653 and 2673. Similarly, outer arcuate magnetic region 2654of primary magnet 2626 and outer arcuate magnetic region 2676 ofauxiliary magnet 2672 can have the same magnetic orientation, as shownby polarity indictors 2655 and 2675. This configuration creates amagnetic attraction between primary magnet 2626 and auxiliary magnet2672, which can facilitate alignment between them. The magnetic polarityof secondary magnet 2628 (shown by indicator 2617) can be oriented suchthat when secondary magnetic alignment component 2618 is aligned withauxiliary magnetic alignment component 2670, the south pole of secondarymagnet 2628 is oriented toward the north pole of inner arcuate magneticregion 2674 of auxiliary magnet 2672 (and also toward the north pole ofinner arcuate magnetic region 2652 of primary magnet 2626) while thenorth pole of secondary magnet 2628 is oriented toward the south pole ofouter arcuate magnetic region 2676 of auxiliary magnet 2672 (and alsotoward the south pole of outer arcuate magnetic region 2654 of primarymagnet 2626).

Accordingly, the respective magnetic orientations of inner arcuatemagnetic regions 2652, 2674, secondary magnet 2628 and outer arcuatemagnetic region 2676, 2678 can generate magnetic fields 2640 that exertan attractive force between primary magnet 2626 and auxiliary magnet2672 and between auxiliary magnet 2672 and secondary magnet 2628,thereby facilitating alignment between respective electronic devices inwhich primary alignment component 2616, auxiliary alignment component2670, and secondary alignment component 2618 are disposed (e.g., asshown in FIG. 24). Shield 2614 at the distal surface of primary magnet2626 can redirect some of magnetic fields 2640 away from regions belowprimary magnet 2626. Further, the “closed-loop” magnetic field 2640formed around central non-magnetized regions 2656 and 2678 can havetight and compact field lines that do not stray outside of primary,auxiliary, and secondary magnets 2626, 2672, 2628 as far as magneticfield 2540 strays outside of primary, auxiliary, and secondary magnets2526, 2572, 2528 in FIG. 25B. Thus, magnetically sensitive componentscan be placed relatively close to primary alignment component 2616 withreduced concern for stray magnetic fields. Accordingly, as compared tomagnetic alignment system 2500, magnetic alignment system 2600 can helpto reduce the overall size of a device in which primary alignmentcomponent 2616 is positioned and can also help reduce noise created bymagnetic field 2640 in adjacent components, such as an inductivereceiving coil positioned inboard of secondary alignment component 2618.

It will be appreciated that magnetic alignment system 2600 isillustrative and that variations and modifications are possible. Forinstance, while primary alignment component 2616, auxiliary alignmentcomponent 2672, and secondary alignment component 2618 are each shown asbeing constructed of eight arcuate magnets, other embodiments may use adifferent number of magnets, such as sixteen magnets, thirty-sixmagnets, or any other number of magnets, and the number of primarymagnets need not be equal to the number of secondary magnets. Similarly,the number of auxiliary magnets need not be equal to either the numberof primary magnets or the number of secondary magnets. In otherembodiments, secondary alignment component 2618 can be formed of asingle, monolithic annular magnet. Similarly, primary alignmentcomponent 2616 and/or auxiliary alignment component 2672 can each beformed of a single, monolithic annular piece of magnetic material withan appropriate magnetization pattern as described above, or primaryalignment component 2616 and/or auxiliary alignment component 2672 caneach be formed of a monolithic inner annular magnet and a monolithicouter annular magnet, with an annular air gap or region of nonmagneticmaterial disposed between the inner annular magnet and outer annularmagnet. However, a construction using multiple arcuate magnets mayimprove manufacturing because smaller arcuate magnets are less brittlethan a single, monolithic annular magnet and are less prone to yieldloss due to physical stresses imposed on the magnetic material duringmanufacturing. It should also be understood that the magneticorientations of the various components or individual magnets do not needto align exactly with the lateral and axial directions. The magneticorientation can have any angle that provides a closed-loop path for amagnetic field through the primary and secondary alignment components.

3.4. Magnetic Orientation for a Closed-Loop Magnetic Alignment System

Any of the magnetic orientations described above with reference to FIG.4, 5, 7, 8A-8C, 9A-9B, or 10 can also be applied to systems that includean auxiliary alignment component. The magnetic orientation of theauxiliary magnets can be made to match that of corresponding primarymagnets.

3.5. Annular Magnetic Alignment Components with Gaps

In examples described above, the primary magnetic alignment component,secondary magnetic alignment component, and auxiliary magnetic alignmentcomponent have annular shapes. As described above (e.g., with referenceto FIG. 3A), the annulus can be completely closed. In other embodiments,the annulus can include one or more gaps, where each gap can be asection of an annulus where magnetic material (or any material) isabsent. An example magnetic alignment component with a gap is describedabove with reference to FIG. 11, and it should be understood that anauxiliary alignment component can also include one or more gaps, e.g.,to accommodate a form factor of an accessory device in which anauxiliary magnetic alignment component is present and/or to accommodateelectronic circuit components that may be present in the accessorydevice. Further, compatible annular alignment components in differentdevices can differ as to the number, size, and/or position of gaps.

3.6. Accessory Devices Incorporating Magnetic Alignment Components

FIG. 27 shows a simplified rear view of an accessory device 2700incorporating an auxiliary magnetic alignment component according tosome embodiments. In the example shown, the accessory deviceincorporates an auxiliary alignment component; however, it should beunderstood that an accessory device can instead incorporate a primary orsecondary magnetic alignment component.

Accessory device 2700 can be, for example, a protective or esthetic casefor a portable electronic device such as smart phone 1200 of FIG. 12A.Accordingly, accessory device 2700 can have a housing 2702, which can bethe same size as (or slightly larger than) smart phone 1200. In someembodiments, housing 2702 can be shaped as a tray that covers the sideand rear surfaces of smart phone 1200, leaving the front (display)surface of smart phone 1200 exposed. Housing 2702 (or portions thereof)can be made of plastic, rubber, silicone, leather, and/or othermaterials. An auxiliary alignment component 2770 can be disposed withinhousing 2702, in a position such that, when smart phone 1200 is insertedinto accessory device 2700 in the preferred orientation, auxiliaryalignment component 2770 is coaxially aligned with secondary alignmentcomponent 1218 of smart phone 1200.

Auxiliary alignment component 2770 can be, for example, animplementation of any of the auxiliary alignment components describedabove and can include an annular arrangement of magnets 2772 withinterfaces 2780, which can be air gaps or interfaces where adjacentmagnets contact one another. Magnets 2772 can have a quad-poleconfiguration as described above; for instance, each magnet 2772 caninclude an inner arcuate region having an axial magnetic orientation ina first direction, an outer arcuate region having an axial magneticorientation in a second direction opposite the first direction, and acentral arcuate region having no distinct magnetic orientation. Althoughnot shown in FIG. 27, auxiliary magnetic alignment component 2770 caninclude one or more gaps between adjacent magnets 2772. In someembodiments, the gap(s) can provide electrical connection paths forwires (or conductive traces) to connect between regions inboard of andoutboard of auxiliary magnetic alignment component 2770, and in someembodiments, the gap(s) can be arranged to allow housing 2702 to have areduced lateral size for use with a smart phone having a smaller formfactor. For instance, the pattern of gaps can match that of magneticalignment component 1218′ of smart phone 1200′ of FIG. 12B.

In some embodiments, it may be desirable to support wireless datatransfer between accessory device 2700 and smart phone 1200, forinstance to allow accessory device 2700 to identify itself to smartphone 1200. Accordingly, in some embodiments, a near-field communication(NFC) coil 2766 can be provided in the region inboard of magneticalignment component 2766. In some embodiments, NFC coil 2766 can coupleto a passive NFC tag that can be read by a suitably configured NFCreader (e.g., in smart phone 1200 of FIG. 12). Example embodiments ofNFC coil 2766 are described in section 5 below.

In the example shown, accessory device 2700 is a passive device whosefunction may be protective and/or esthetic. As such, it may be desirableto make accessory device 2700 thin and to provide smooth inner and outersurfaces. In some embodiments, magnets 2772 can have a thin axialdimension so that accessory device 2700 can have smooth surfaces and adesired thinness. Accessory device 2700 can have a variety of shapes andfeatures. For example, accessory device 2700 can be a tray that coversthe side and rear surfaces of smart phone 1200, leaving the front(display) surface of smart phone 1200 exposed. Alternatively, accessorydevice 2700 can include a cover that can be folded over the frontsurface of smart phone 1200 and unfolded to allow access to the display.As another example, accessory device 2700 can be formed as a sleevehaving an opening at one end (e.g., the top end or a side) to allowsmart phone 1200 to be inserted into the sleeve when not in use andremoved from the sleeve for use.

In the example shown, accessory device 2700 can a passive device thatdoes not contain power-consuming components. Accordingly, the region2711 inboard of annular alignment component 2770 can be made of the samematerial as the surrounding housing 2702, providing a continuous backsurface for accessory device 2700. Alternatively, part or all of region2711 may be devoid of material, allowing the corresponding portion ofthe rear surface of smart phone 1200 to be exposed. In some embodiments,housing 2702 of accessory device 2700 (or portions thereof) can be madeof transparent material so that the rear surface of smart phone 1200 (orportions thereof) can be seen through accessory device 2700. In theabsence of transparent magnetic material, an annular region of opaquematerial can be disposed over magnetic alignment component 2770 so thatthe individual magnets are not visible. The opaque material can have acolor (or colors) selected for a desired esthetic effect.

In some embodiments, accessory 2700 can be an active device. Forexample, accessory 2700 can include an external battery that can providepower to smart phone 1200. Accordingly, central region 2711 can includeone or more wireless charging coils, which can be arranged and operatedas described above with reference to accessory 2420 of FIG. 24.

3.7. Wireless Charging Systems with Magnetic Alignment

FIG. 28A shows a simplified perspective view of a system 2800 includingportable electronic device 1200 (of FIG. 12A) in alignment withaccessory device 2700 (of FIG. 27) and wireless charger device 1300 (ofFIG. 13) according to some embodiments. In FIG. 28A, portions ofwireless charger device 1300 and accessory device 2700 are shown usingdashed lines to avoid obscuring other details. As shown, accessorydevice 2700 can be placed adjacent to portable electronic device 1200,for example by inserting portable electronic device 1200 into accessorydevice 2700, and wireless charger device 1300 can be placed with itscharging (or proximal) surface against the rear (or proximal) surface2803 of accessory device 2700. When the devices are placed in thisarrangement, secondary alignment component 1218 in portable electronicdevice 1200 is aligned with auxiliary alignment component 2770 ofaccessory device 2700 and with primary alignment component 1316 ofwireless charger device 1300. Accordingly, auxiliary alignment component2770 in accessory device 2700 and secondary alignment component 1218 inportable electronic device 120 can attract and hold primary magneticalignment component 1316 of wireless charger device 1300 in alignment sothat transmitter coil assembly 1312 of wireless charger device 1300 isaligned with coil assembly 1210 of portable electronic device 1200. Asshown, wireless charger device 1300 can have any rotational orientationabout an axis defined by the centers of primary magnetic alignmentcomponent 1316 and secondary magnetic alignment component 1218; forinstance, gap 1201 in secondary magnetic alignment component 1218 neednot align with gap 1301 in primary magnetic alignment component 1316.

FIG. 28B shows a simplified partial cross section view of system 2800according to some embodiments. Portable electronic device 1200 has arear housing 2802 (which can be made of a material such as glass orplastic that is permeable to electromagnetic fields and to DC magneticfields) and a front housing 2804 (which can include a touch screendisplay). Coil assembly 1210 can include an inductive receiver coil 2810(which can be made, e.g., of stranded wire wound into a coil) andshielding 2812 (which can include, e.g., a ferrimagnetic shield).Secondary magnet 2828 forms a portion of secondary magnetic alignmentcomponent 1218 and can have a magnetic field oriented in a radiallyinward direction (as shown by the arrow). It should be understood thatalthough secondary alignment component 1218 is shown in FIG. 28A, rearhousing 2802 can be opaque and secondary alignment component 1218 neednot be visible to a user.

Wireless charger device 1300 has a housing 1302 that includes asingle-piece enclosure 2806 forming distal and side surfaces of housing1302 and a top cap 2808 forming a proximal surface of housing 1302. Asdescribed above, enclosure 2806 and top cap 2808 can be made of the samematerial or different materials, and top cap 2808 can be made of amaterial that is permeable to AC electromagnetic fields and to DCmagnetic fields. Transmitter coil assembly 1312 can include an inductivetransmitter coil 2816 (which can be made, e.g., of stranded wire woundinto a coil) and electromagnetic shielding 2814 (which can include,e.g., a ferrimagnetic shield). Primary arcuate magnet 2826 forms aportion of primary magnetic alignment component 1316 and can include aninner arcuate region 2852 having a magnetic field oriented in a firstaxial direction, an outer arcuate region 2854 having a magnetic fieldoriented in a second axial direction opposite the first axial direction,and a non-magnetized central arcuate region 2856. As described above, ashield 2814 can be disposed on the distal surface of primary magnet2826. It should be understood that although primary alignment component1316 is shown in FIG. 28A, housing 1302 can be opaque and primaryalignment component 1316 need not be visible to a user.

Accessory device 2700 has a rear housing 2702 that includes a back layer2805 (forming back surface 2803) and a front layer 2807 that contactsrear housing 2802 of portable electronic device 1200 at a surface 2809.Back layer 2805 and front layer 2807 can be made of the same material ordifferent materials as desired. Auxiliary arcuate magnet 2872 forms aportion of auxiliary alignment component 2770 and can include an innerarcuate section 2874 having a magnetic field oriented in a first axialdirection, an outer arcuate section 2876 having a magnetic fieldoriented in a second axial direction opposite the first axial direction,and a non-magnetized central arcuate section 2878. It should beunderstood that although auxiliary alignment component 2770 is shown inFIG. 28A, rear housing 2702 can be opaque and auxiliary alignmentcomponent 2770 need not be visible to a user.

When aligned, primary magnet 2826, auxiliary magnet 2872, and secondarymagnet 2828 produce a closed-loop magnetic flux as shown by lines 2840.Magnetic flux 2840 can attract primary annular alignment component 1318,auxiliary annular alignment component 2770 and secondary annularalignment component 1216 into alignment such that the respective centersof primary annular alignment component 1318, auxiliary annular alignmentcomponent 2770, and secondary annular alignment component 1216 arealigned along a common axis. Since transmitter coil 2816 is fixed in aposition concentric with primary alignment component 1316 and receivercoil 2810 is fixed in position concentric with secondary alignmentcomponent 1218, a result of aligning primary annular alignment component1318, auxiliary annular alignment component 2770, and secondary annularalignment component 1216 along a common axis is that transmitter coil2816 and receiver coil 2810 are also aligned along a common axis,thereby enabling efficient wireless power transfer. For instance,transmitter coil 2816 can be driven with an alternating current togenerate time-varying magnetic fields that induce a time-varying currentin receiver coil 2816. Electromagnetic shielding (e.g., shielding 2814and 2812) can confine the AC fields to the immediate vicinity of coils2816 and 2812. Further, in embodiments where accessory device 2700includes one or more wireless charging coils, such wireless chargingcoils can also be aligned along a common axis with coils 2816 and 2810.

Some embodiments provide a gap region 2811 between secondary magnet 2828and coil assembly 1210 that may experience low DC magnetic flux and mayalso experience low AC electromagnetic fields due to electromagneticshielding 2812 around coil 2810. Similarly, some embodiments provide agap region 2813 between primary magnet 2826 and transmitter coilassembly 1312 that may experience low DC magnetic flux and may alsoexperience low AC electromagnetic fields due to electromagneticshielding 2818 around transmitter coil 2816. In some embodiments, NFCantenna coils (not shown) may be placed in gap region 2811 and/or 2813,e.g., to support identification of wireless charger device 1300 byportable electronic device 1200. Similarly, an NFC antenna coil (notshown) may be placed in a corresponding region 2815 between back layer2805 and front layer 2807 of accessory device 2700, e.g., to supportidentification of accessory device 2700 by portable electronic device1200. Example embodiments of NFC antenna coils that may be placed in gapregions 2811, 2813 and/or 2815 are described in section 5 below.

As can be appreciated with reference to FIG. 28B, arcuate magnets 2828of secondary alignment component 1218 can have a thin axial dimension sothat secondary alignment component 1218 does not require an increasedthickness of portable electronic device 1200. For instance, the axialthickness of each secondary alignment magnet 2828 can be less than orequal to the thickness of receiver coil assembly 1210 (including coil2810 and shielding 2812). Primary alignment magnets 2826 can have athicker axial dimension, e.g., occupying all of the axial space betweenenclosure 2806 and top cover 2808.

Similarly, each arcuate magnet 2872 of auxiliary alignment component2770 can have a thin axial dimension so that the overall thickness ofaccessory device 2700 can be kept small. Back layer 2805 and front layer2807 can be planar layers. Space between layers 2805 and 2807 that isnot occupied by auxiliary alignment magnets 2872 can be an air gap, orportions or all of the space may be filled with material. In someembodiments, surfaces 2803 and 2809 do not evince a local deviation fromflatness due to the presence of auxiliary alignment magnets 2872. Insome embodiments, accessory device 2700 (or a back housing elementthereof) can be formed as a single piece of material with auxiliaryalignment component 2770 embedded therein. Auxiliary alignment magnets2872 and primary alignment magnets 2826 can have the same radial width;in some embodiments, the radial width of auxiliary alignment magnets2872 and primary alignment magnets 2826 can be slightly larger than theradial width of secondary alignment magnets 2828.

It should be understood that auxiliary alignment component 2770 isoptional, and a charge-through accessory that does not have an auxiliaryalignment component may be positioned between portable electronic device1200 and wireless charger device 1300. Depending on the thickness andmaterial composition of the accessory, primary annular alignmentcomponent 1316 and secondary annular alignment component 1218 may stillexperience sufficient attraction to provide reliable alignment betweencoils 2816 and 2810. However, for DC magnets, the attractive forcediminishes sharply with increasing distance between magnets, so thealignment may be less strong. Accordingly, auxiliary alignment component2770 can be used as a “repeater” that decreases the distance betweenadjacent magnets and thus increases the magnetic force that urges towardalignment.

FIG. 29 is a block diagram illustrating an exemplary wireless chargingsystem 2900 including a portable electronic device 2904 (which can be,e.g., portable electronic device 1200 or any other portable electronicdevice described herein), a wireless charger device 2902 (which can be,e.g., wireless charger device 1300 or any other wireless charger devicedescribed herein), and an accessory device 2906 (which can be, e.g.,accessory device 2800 or any other accessory device described herein)that can be aligned together via a magnetic alignment system 2908according to some embodiments. Magnetic alignment system 2908 caninclude a primary alignment component 2916 within wireless chargerdevice 2902, a secondary alignment component 2918 within portableelectronic device 2904, and an auxiliary alignment component 2970 withinaccessory device 2906. Primary alignment component 2916, secondaryalignment component 2918, and auxiliary alignment component 2970 can beconstructed according to any of the embodiments described herein.Portable electronic device 2904 can include a computing system 2941coupled to a memory bank 2942. Computing system 2941 can include controlcircuitry configured to execute instructions stored in memory bank 2942for performing various functions for operating portable electronicdevice 2904. The control circuitry can include one or more programmableintegrated logic circuits, such as microprocessors, central processingunits (CPUs), graphics processing units (GPUs), field programmable gatearrays (FPGAs), or the like.

Computing system 2941 can also be coupled to a user interface system2943, a communication system 2944, and a sensor system 2945 for enablingportable electronic device 2904 to perform one or more functions. Forinstance, user interface system 2943 can include a display, speaker,microphone, actuator for enabling haptic feedback, and one or more inputdevices such as a button, switch, capacitive screen for enabling thedisplay to be touch sensitive, and the like. Communication system 2944can include wireless telecommunication components, NFC components,Bluetooth components, and/or Wi-Fi components for enabling portableelectronic device 2904 to make phone calls, interact with wirelessaccessories, and access the Internet. In some embodiments, communicationsystem 2944 can include NFC reader circuitry that is used in connectionwith magnetic alignment system 2906 to identify one or more aligneddevices; examples are described in section 5 below. Sensor system 2945can include light sensors, accelerometers, gyroscopes, temperaturesensors, magnetometers, and/or any other type of sensor that can measurea parameter of an external entity and/or environment.

All of these electrical components require a power source to operate.Accordingly, portable electronic device 2904 also includes a battery2946 that can discharge stored energy to power the electrical componentsof portable electronic device 2904. To replenish the energy dischargedto power the electrical components, portable electronic device 2904includes charging circuitry 2947 and an inductive coil 2910 that canreceive power from wireless charger device 2902 coupled to an externalpower source 2922.

Wireless charger device 2902 can include a transmitter coil 2912 forgenerating time-varying magnetic flux capable of inducing an electricalcurrent in coil 2910 of portable electronic device 2904. The inducedcurrent can be used by charging circuitry 2947 to charge battery 2946.Wireless charger device 2902 can further include a computing system 2921coupled to a communication system 2922 and wireless charging circuitry2923. Wireless charging circuitry can include circuit components toconvert standard AC power having a first set of voltage and frequencycharacteristics (e.g., standard AC wall power) to AC power suitable foroperating coil 2910. Suitable circuit components, including rectifiers(AC-to-DC converters), boost circuits (DC-to-DC voltage boostingcircuits), inverters (DC-to-AC converters), and the like, are known inthe art. Computing system 2921 can include logic circuitry (such as amicroprocessor, microcontroller, FPGA, or the like) configured tocontrol the operation of wireless charger device 2902, such as tocontrol wireless charging circuitry 2923 to use power received fromexternal power source 2922 to generate time-varying magnetic flux toinduce current in coil 2910 to charge portable electronic device 2904.In some embodiments, computing system 2921 can implement functionalityconfirming to the Qi standard for wireless charging (promulgated by theWireless Power Consortium).

In some embodiments, components implementing computing system 2921 andwireless charging circuitry 2923 can be disposed within the housing thatholds coil 2912 and primary alignment component 2916 (e.g., withinpuck-shaped housing 1302 of FIGS. 13 and 14A-14B). In other embodiments,some or all of the components implementing computing system 2921 andwireless charging circuitry 2923 can be disposed elsewhere, e.g., at thedistal end of cable 1304 in FIGS. 13 and 14A. For example, the logiccircuitry implementing computing system 2921 can be disposed withinhousing 1302 while wireless charging circuitry 2932 is disposed in aboot of a plug connector at the distal end of cable 1304. (In this case,cable 1304 can provide AC power to wireless charger device 1300.) Asanother example, the logic circuitry implementing computing system 2921and circuit components implementing portions of wireless chargingcircuitry 2923 can be disposed within housing 1302 while circuitcomponents implementing other portions of wireless charging circuitry2923 are disposed in a boot of a plug connector at the distal end ofcable 1304. For instance, an inverter may be disposed within housing1302 while a rectifier and boost circuit are disposed in the boot. (Inthis case, cable 1304 can provide DC power to wireless charger device1300.)

As described above, accessory device 2906 can be a passive accessorysuch as protective case for portable electronic device 1002 and need notinclude any components other than auxiliary alignment component 2970. Insome embodiments, accessory device 2906 can be an active device. Forinstance, accessory device 2906 can include a computing system 2961coupled to a memory bank 2962 and a communication system 2963. Computingsystem 2961 can execute instructions stored in memory bank 2962 toperform one or more functions using communication system 2963. In someembodiments, computing system 2961 can be configured to send data frommemory bank 2962 through communication system 2963 to portableelectronic device 2904 regarding a user interface theme for portableelectronic device 2904 so that portable electronic device 2904 can usethis data to modify its user interface. As an example, accessory device2906 can be a protective case that has a picture of a car on it, andmemory bank 2962 has information stored for configuring a user interfaceto include a car theme with car-related icons, animations, and/orsounds. Thus, when accessory device 2906 is installed on portableelectronic device 2902, computing system 2941 can receive the car-themeduser interface from accessory device 2906 and can modify user interfacesystem 2943 according to the received car-themed data (e.g., changingwhat is displayed, what sounds are played to signal events, etc.). Insome embodiments, accessory device 2906 can also include a wirelesscharging component 2964 that can aid in wireless charging betweenportable electronic device 2904 and wireless charger device 2902. Forinstance, wireless charging component 2964 can include a block ofmagnetic material that can help guide magnetic flux through accessorydevice 2906. Or, wireless charging component 2964 can include a pair ofinductor coils where one inductor coil positioned proximate to wirelesscharger device 2902 can receive magnetic flux, which can be relayed tothe other inductor coil positioned proximate to portable electronicdevice 2904 so that the received flux can be retransmitted to portableelectronic device 2904. In some embodiments, accessory device 2906 caninclude a battery (not shown) to store power received from wirelesscharger device 2902 at a first time for delivery to portable electronicdevice 2904 at a later time.

While system 2900 is described with reference to particular blocks, itis to be understood that these blocks are defined for convenience ofdescription and are not intended to imply a particular physicalarrangement of component parts. The blocks need not correspond tophysically distinct components, and the same physical components can beused to implement aspects of multiple blocks. Blocks can be configuredto perform various operations, e.g., by programming a processor orproviding appropriate control circuitry, and various blocks might ormight not be reconfigurable depending on how the initial configurationis obtained. Embodiments of the present invention can be realized in avariety of apparatus including electronic devices that use using anycombination of circuitry and software to enable wireless chargingoperations and/or other operations where physical alignment betweendevices is desired.

4. Systems with Movable Magnetic Alignment Components

In embodiments described above, it is assumed (though not required) thatthe magnetic alignment components (including annular magnetic alignmentcomponents, and, where applicable, rotational magnetic alignmentcomponents) are fixed in position relative to the device housing (orenclosure) and do not move in the axial or lateral direction. Thisprovides a fixed magnetic flux. In some embodiments, it may be desirablefor one or more of the magnetic alignment components to move in theaxial direction. For example, in various embodiments of the presentinvention, it can be desirable to limit the magnetic flux provided bythese magnetic structures. Limiting the magnetic flux can help toprevent the demagnetization of various charge and payment cards that auser might be carrying with an electronic device that incorporates oneof these magnetic structures. But in some circumstances, it can bedesirable to increase this magnetic flux in order to increase a magneticattraction between an electronic device and an accessory or a secondelectronic device. Also, it can be desirable for one or more of themagnetic alignment components to move laterally. For example, anelectronic device and an attachment structure or wireless device can beoffset from each other in a lateral direction. The ability of a magneticalignment component to move laterally can compensate for this offset andimprove coupling between devices, particularly where a coil moves withthe magnetic alignment component. Accordingly, embodiments of thepresent invention can provide structures where some or all of themagnets in these magnetic structures are able to change positions orotherwise move. Examples of magnetic structures having moving magnetsare shown in the following figures.

FIGS. 30A-30C illustrate examples of moving magnets according to anembodiment of the present invention. In this example, first electronicdevice 3000 can be a wireless charger device or other device having amagnet 3010 (which can be, e.g., any of the annular or rotationalmagnetic alignment components described herein). In FIG. 30A, movingmagnet 3010 can be housed in a first electronic device 3000. Firstelectronic device 3000 can include device enclosure 3030, magnet 3010,and shield 3020. Magnet 3010 can be in a first position (not shown)adjacent to nonmoving shield 3020. In this position, magnet 3010 can beseparated from device enclosure 3030. As a result, the magnetic flux3012 at a surface of device enclosure 3030 can be relatively low,thereby protecting magnetic devices and magnetically stored information,such as information stored on payment cards. As magnet 3010 in firstelectronic device 3000 is attracted to a second magnet (not shown) in asecond electronic device (not shown), magnet 3010 can move, for exampleit can move away from shield 3020 to be adjacent to device enclosure3030, as shown. With magnet 3010 at this location, magnetic flux 3012 atsurface of device enclosure 3030 can be relatively high. This increasein magnetic flux 3012 can help to attract the second electronic deviceto first electronic device 3000.

With this configuration, it can take a large amount of magneticattraction for magnet 3010 to separate from shield 3020. Accordingly,these and other embodiments of the present invention can include ashield that is split into a shield portion and a return plate portion.For example, in FIG. 30B, line 3060 can be used to indicate a split ofshield 3020 into a shield 3040 and return plate 3050.

In FIG. 30C, moving magnet 3010 can be housed in first electronic device3000. First electronic device 3000 can include device enclosure 3030,magnet 3010, shield 3040, and return plate 3050. In the absence of amagnetic attraction, magnet 3010 can be in a first position (not shown)such that shield 3040 can be adjacent to return plate 3050. Again, thisconfiguration, magnetic flux 3012 at a surface of device enclosure 3030can be relatively low. As magnet 3010 and first electronic device isattracted to a second magnet (not shown) in a second electronic device(not shown), magnet 3010 can move, for example it can move away fromreturn plate 3050 to be adjacent to device enclosure 3030, as shown. Inthis configuration, shield 3040 can be separate from return plate 3050and the magnetic flux 3012 at a surface of device enclosure 3030 can beincreased. As before, this increase in magnetic flux 3012 can help toattract the second electronic device to the first electronic device3000.

In these and other embodiments of the present invention, varioushousings and structures can be used to guide a moving magnet. Also,various surfaces can be used in conjunction with these moving magnets.These surfaces can be rigid. Alternatively, these surfaces can becompliant and at least somewhat flexible. Examples are shown in thefollowing figures.

FIGS. 31A and 31B illustrate a moving magnetic structure according to anembodiment of the present invention. In this example, first electronicdevice 3100 can be a wireless charger device or other device having afirst magnet 3110 (which can be, e.g., any of the annular or rotationalmagnetic alignment components described herein). FIG. 31A illustrates amoving first magnet 3110 in a first electronic device 3100. Firstelectronic device 3100 can include first magnet 3110, protective surface3112, housings 3120 and 3122, compliant structure 3124, shield 3140, andreturn plate 3150. In this figure, first magnet 3110 is not attracted toa second magnet (not shown), and therefore shield 3140 is magneticallyattracted to or attached to return plate 3150. In this position,compliant structure 3124 can be expanded or relaxed. Compliant structure3124 can be formed of an elastomer, silicon rubber open cell foam,silicon rubber, polyurethane foam, or other foam or other compressiblematerial.

In FIG. 31B, second electronic device 3160 has been brought intoproximity of first electronic device 3100. Second magnet 3170 canattract first magnet 3110, thereby causing shield 3140 and return plate3150 to separate. Housings 3120 and 3122 can compress compliantstructure 3124, thereby allowing protective surface 3112 of firstelectronic device 3100 to move towards or adjacent to housing 3180 ofsecond electronic device 3160. Second magnet 3170 can be held in placein second electronic device 3160 by housing 3190 or other structure. Assecond electronic device 3160 is removed from first electronic device3100, first magnet 3110 and shield 3140 can be magnetically attracted toreturn plate 3150, as shown in FIG. 31A.

FIGS. 32A and 32B illustrate moving magnetic structures according to anembodiment of the present invention. In this example, first electronicdevice 3200 can be a wireless charger device or other device having afirst magnet 3210 (which can be, e.g., any of the annular or rotationalmagnetic alignment components described herein). FIG. 32A illustrates amoving first magnet 3210 in a first electronic device 3200. Firstelectronic device 3200 can include first magnet 3210, pliable surface3212, housing portions 3220 and 3222, shield 3240, and return plate3250. In this figure, first magnet 3210 is not attracted to a secondmagnet, and therefore shield 3240 is magnetically attached or attractedto return plate 3250. In this position, pliable surface 3212 can berelaxed. Pliable surface 3212 can be formed of an elastomer, siliconrubber open cell foam, silicon rubber, polyurethane foam, or other foamor other compressible material.

In FIG. 32B, second electronic device 3260 has been brought into theproximity of first electronic device 3200. Second magnet 3270 canattract first magnet 3210, thereby causing shield 3240 and return plate3250 to separate from each other. First magnet 3210 can stretch pliablesurface 3212 towards second electronic device 3260, thereby allowingfirst magnet 3210 of first electronic device 3200 to move towardshousing 3280 of second electronic device 3260. Second magnet 3270 can beheld in place in second electronic device 3260 by housing 3290 or otherstructure. As second electronic device 3260 is removed from firstelectronic device 3200, first magnet 3210 and shield 3240 can bemagnetically attracted to return plate 3250 as shown in FIG. 32A.

FIGS. 33-35 illustrate a moving magnetic structure according to anembodiment of the present invention. In this example, first electronicdevice 3300 can be a wireless charger device or other device having afirst magnet 3310 (which can be, e.g., any of the annular or rotationalmagnetic alignment components described herein). In FIG. 33, firstmagnet 3310 and shield 3340 can be magnetically attracted or attached toreturn plate 3350 in first electronic device 3300. First electronicdevice 3300 can be at least partially housed in device enclosure 3320.In FIG. 34, housing 3380 of second electronic device 3360 can movelaterally across a surface of device enclosure 3320 of first electronicdevice 3300 in a direction 3385. Second magnet 3370 in second electronicdevice 3360 can begin to attract first magnet 3310 in first electronicdevice 3300. This magnetic attraction 3315 can cause first magnet 3310and shield 3340 to pull away from return plate 3350 by overcoming themagnetic attraction 3345 between shield 3340 and return plate 3350. InFIG. 35, second magnet 3370 in second electronic device 3360 has becomealigned with first magnet 3310 in first electronic device 3300. Firstmagnet 3310 and shield 3340 have pulled away from return plate 3350thereby reducing the magnetic attraction 3345. First magnet 3310 hasmoved nearby or adjacent to device enclosure 3320, thereby increasingthe magnetic attraction 3315 to second magnet 3370 in second electronicdevice 3360.

As shown in FIGS. 33-35, the magnetic attraction between first magnet3310 in first electronic device 3300 and the second magnet 3370 in thesecond electronic device 3360 can increase when first magnet 3310 andshield 3340 pull away from return plate 3350. This is shown graphicallyin the following figures.

FIG. 36 illustrates a normal force between a first magnet in firstelectronic device and a second magnet in a second electronic device as afunction of a lateral offset between them. As shown in FIGS. 33-36, witha large offset between first magnet 3310 and second magnet 3570, firstmagnet 3310 and shield 3340 can remain attached to return plate 3350 infirst electronic device 3300 and the magnetic attraction 3315 can beminimal. The shear force necessary to overcome this magnetic attractionis illustrated here as curve 3610. As shown in FIG. 34, as the offset orlateral distance between first magnet 3310 and second magnet 3370decreases, first magnet 3310 and shield 3340 can pull away or separatefrom return plate 3350, thereby increasing the magnetic attraction 3315between first magnet 3310 and second magnet 3370. This is illustratedhere as discontinuity 3620. As shown in FIG. 35, as first magnet 3310and second magnet 3370 come into alignment, the magnetic attraction 3315increases along curve 3630 to a maximum 3640. The difference betweencurve 3610 and curve 3630 can show the increase in magnetic attractionbetween a phone or other electronic device, such as second electronicdevice 3360, and an attachable wireless charging device or otheraccessory device, such as first electronic device 3300, that resultsfrom first magnet 3310 being able to move axially. It should also benoted that in this example first magnet 3310 does not move in a lateraldirection, though in other examples it is capable of such movement.Where first magnet 3310 is capable of moving in a lateral direction,curve 3630 can have a flattened peak from an offset of zero to an offsetthat can be overcome by a range of possible lateral movement of firstmagnet 3310.

FIG. 37 illustrates a sheer force between a first magnet in a firstelectronic device and a second magnet in a second electronic device as afunction of a lateral offset between them. With no offset between firstmagnet 3310 and second magnet 3360, there it is no shear force to movesecond magnet 3370 relative to first magnet 3310, as shown in FIG. 33.As the offset is increased, the shear force, that is the forceattempting to realign the magnets, can increase along curve 3740. Atdiscontinuity 3710, first magnet 3310 and shield 3340 can return toreturn plate 3350 (as shown in FIGS. 33-42), thereby decreasing themagnetic shear force to point 3720. The magnetic sheer force cancontinue to drop off along curve 3730 as the offset increases. Thedifference between curve 3730 and curve 3740 can show the increase inmagnetic attraction between a phone or other electronic device, such assecond electronic device 3360 and an attachable wireless charging deviceor other accessory device, such as first electronic device 3300, thatresults from first magnet 3310 being able to move axially. It shouldalso be noted that in this example first magnet 3310 does not move in alateral direction, though in other examples it is capable of suchmovement. Where first magnet 3310 is capable of moving in a lateraldirection, curve 3730 can remain at zero until the lateral movement ofthe second magnet 3370 overcomes the range of possible lateral movementof first magnet 3310.

In these and other embodiments of the present invention, it can bedesirable to further increase this sheer force. Accordingly, embodimentsof the present invention can provide various high friction or highstiction surfaces, suction cups, pins, or other structures to increasethis sheer force. Examples are shown in the following figures.

FIGS. 38A and 38B illustrate a moving magnet in conjunction with a highfriction or high stiction surface according to an embodiment of thepresent invention. In this example, first electronic device 3800 can bea wireless charger device or other device having a first magnet 3810(which can be, e.g., any of the annular magnetic alignment componentsdescribed above). In FIG. 38A, first magnet 3810 and shield 3840 can bemagnetically attracted or attached to return plate 3850 in firstelectronic device 3800. First electronic device 3800 can be housed indevice enclosure 3820. Some or all of a surface of device enclosure 3820can have a coating, layer, or other structure 3822. Structure 3822 canprovide a high friction or high stiction surface. In FIG. 38B, firstmagnet 3810 and shield 3840 can be attracted to a second magnet (notshown) in a second electronic device (not shown). As before, theseparation of first magnet 3810 and shield 3840 from return plate 3850can provide an increased amount of magnetic flux to hold the secondelectronic device in place relative to first electronic device 3800.Structure 3822 can increase the friction or stiction between firstelectronic device 3800 and the second electronic device in a lateral orshear direction.

FIGS. 39A and 39B illustrate a moving magnet in conjunction with a highfriction or high stiction surface according to an embodiment of thepresent invention. In this example, first electronic device 3900 can bea wireless charger device or other device having a first magnet 3910(which can be, e.g., any of the annular or rotational magnetic alignmentcomponents described herein). In FIG. 39A, first magnet 3910 and shield3940 can be magnetically attracted or attached to return plate 3950 infirst electronic device 3900. First electronic device 3900 can be housedin device enclosure 3920. Some or all of a surface of device enclosure3920 can have a coating, layer, or other structure 3922, in this exampleover first magnet 3910. Structure 3922 can provide a high friction orhigh stiction surface. In FIG. 39B, first magnet 3910 and shield 3940can be attracted to a second magnet (not shown) in a second electronicdevice (not shown.) This can cause first magnet 3910 and shield 3940 toseparate from return plate 3850, thereby deforming structure 3922, whichcan be pliable or compliant. As before, first magnet 3910 can provide anincreased amount of magnetic flux to hold the second electronic devicein place relative to first electronic device 3900. Structure 3922 canincrease the friction or stiction between first electronic device 3900and the second electronic device in a lateral or sheer direction.

FIGS. 40A and 40B illustrate a moving magnet in conjunction with a highfriction surface according to an embodiment of the present invention. Inthis example, first electronic device 4000 can be a wireless chargerdevice or other device having a first magnet 4010 (which can be, e.g.,any of the primary annular magnetic alignment components describedabove). In FIG. 40A, first magnet 4010 and shield 4040 can bemagnetically attracted or attached to return plate 4050 in firstelectronic device 4000. First electronic device 4000 can be housed indevice enclosure 4020. Some or all of a surface of device enclosure 4020can have a coating, layer, or other structure 4022, in this example overa top surface of first electronic device 4000. Structure 4022 canprovide a high friction or high stiction surface. In FIG. 40B, firstmagnet 4010 and shield 4040 can be attracted to a second magnet (notshown) in a second electronic device (not shown.) The separation offirst magnet 4010 and shield 4040 from return plate 4050 can push thetop surface formed by structure 4022 upward where it can engage thesecond electronic device with a high-friction surface. As before, firstmagnet 4010 can provide an increased amount of magnetic flux to hold thesecond electronic device in place relative to first electronic device4000. Structure 4022 can increase the friction or stiction between firstelectronic device 4000 and the second electronic device in a lateral orsheer direction.

FIGS. 41A and 41B illustrate another moving magnet in conjunction with ahigh friction or high stiction surface according to an embodiment of thepresent invention. In this example, first electronic device 4100 can bea wireless charger device or other device having a first magnet 4110(which can be, e.g., any of the annular magnetic alignment componentsdescribed above). In FIG. 41A, first magnet 4110 and first shield 4150can be fixed in place in device enclosure 4120 of first electronicdevice 4100. Some or all of a surface of device enclosure 4120 can havea coating, layer, or other structure 4122. Structure 4122 can provide ahigh friction or high stiction surface. First electronic device 4100 canfurther include a moving second magnet 4191 and second shield 4192,which can be attached to sliding mechanism 4190. In FIG. 41B, as asecond electronic device (not shown) comes into contact with firstelectronic device 4100, sliding mechanism 4190 can be depressed, therebymoving second magnet 4191 away from second shield 4192 and the topsurface of device enclosure 4120. The polarity of second magnet 4191 canbe in opposition to, or the opposite of, the polarity of first magnet4110, such that the net magnetic flux at a top surface of deviceenclosure 4120 is increased as sliding mechanism 4190 is depressed.Structure 4122 can increase the friction or stiction between firstelectronic device 4100 and the second electronic device in a lateral orsheer direction.

FIG. 43 is a partially transparent view of the moving magnet structureof FIG. 42. First electronic device 4200 can be housed in deviceenclosure 4220. As before, first electronic device 4200 can includeinductive charging, near field communication complements, or otherelectronic circuits for components 4278. Return plates 4250 (shown inFIG. 42) can be attached to beams 4270.

FIG. 44 is another cutaway side view of the electronic device of FIG.42. First electronic device 4200 can be housed in device enclosure 4220.As before, first electronic device 4200 can include inductive charging,near field communication components, or other electronic circuits forcomponents 4278. Return plates 4250 can be attached to beams 4270. Firstmagnets 4210 and shield 4240 can be attracted or attached to returnplate 4250. A high friction or high stiction structure 4222 can coversome or all of a top surface of first electronic device 4200. Beams 4270can be attached to return plates 4250, can be anchored at points 4274,and can have a tip 4272 extending above top surface of device enclosure4220.

FIGS. 45 and 46 illustrate the electronic device of FIG. 42 as itengages with a second electronic device. In FIG. 45, second electronicdevice 4280 can include second magnets 4290. Second electronic device4280 can engage with first electronic device 4200. First electronicdevice 4200 can include first magnets 4210, shields 4240, and returnplates 4250. Return plates 4250 can be attached to beams 4270. Beams4270 can include tips 4272 which can extend above a top surface ofdevice enclosure 4220. Tips 4272 can prevent second electronic device4280 from engaging with the high friction or high stiction structure4222 of first electronic device 4200 until the second electronic device4280 is aligned, or nearly aligned, with first electronic device 4200.Beams 4270 can be attached at points 4274 to device enclosure 4220.First electronic device 4200 can include components 4278.

In FIG. 46, second electronic device 4280 can be aligned with the firstelectronic device 4200. When this occurs, first magnets 4210 and shields4240 can detach from return plates 4250. This can increase magnetic fluxbetween second magnets 4290 in second electronic device 4280 and firstmagnets 4210 and first electronic device 4200. Tips 4272 can becomedepressed into device enclosure 4220 due to this increase magneticattraction, thereby further pushing return plates 4250 away from shields4240. High friction or high stiction structure 4222 can engage withsecond electronic device 4280 to increase the shear force necessary fora detachment of second electronic device 4280 from first electronicdevice 4200.

In these and other embodiments of the present invention, variousstructures can be used to constrain movement of magnets in an electronicdevice. Examples are shown in the following figures.

FIGS. 47A and 47B illustrate structures for constraining motions ofmagnets in an electronic device according to an embodiment of thepresent invention. In this example, first electronic device 4700 can bea wireless charger device or other device having a first magnet 4710(which can be, e.g., any of the annular magnetic alignment componentsdescribed above). In FIG. 47A, magnet 4710, shield 4740, and structure4770 can be housed by device enclosure 4720 in electronic device 4700.Structure 4770 can include notch 4772, which can fit in tab 4724. InFIG. 47B, magnet 4710 has moved, taking along with it shield 4740 andstructure 4770. Notch 4772 accepts tab 4724 as shield 4740 detaches fromreturn plate 4750. This can constrain the motion of magnets 4710 inelectronic device 4700. Electronic device 4700 can include a top deviceenclosure portion 4722. Tab 4724 can be formed as part of or separatefrom top device enclosure portion 4722.

FIGS. 48A and 48B illustrate structures for constraining motions ofmagnets in an electronic device according to an embodiment of thepresent invention. In this example, first electronic device 4800 can bea wireless charger device or other device having a first magnet 4810(which can be, e.g., any of the annular magnetic alignment componentsdescribed above). In FIG. 48A, magnet 4810, shield 4840, and returnplate 4850 can be housed in device enclosure 4820 of electronic device4800. Top device enclosure portion 4822 can include guide 4824. Guide4824 can constrain motion of magnet 4810 in electronic device 4800. InFIG. 48B, magnet 4810 and shield 4840 have detached from return plate4850 and have been guided into position by guide 4824. Guide 4824 caninclude one or more chamfered edges 4825. Again, guide 4824 can beformed along with or separate from top device enclosure portion 4822 ofelectronic device 4800.

FIGS. 49A and 49B illustrate structures for constraining motions ofmagnets in an electronic device according to an embodiment of thepresent invention. In this example, first electronic device 4900 can bea wireless charger device or other device having a first magnet 3010(which can be, e.g., any of the annular magnetic alignment componentsdescribed above). In FIG. 49A, magnet 4910, shield 4940, and returnplate 4950 can be housed in device enclosure 4920 of electronic device4900. Magnet 4910 and shield 4940 can be supported by structure 4970.Structure 4970 can be attached to anchor 4974 through actuators 4972.Actuators 4972 can have hinges 4973 and 4975 at each end to allowstructure 4970 to move relative to anchor 4974. Anchor 4974 can beattached to, or formed as either part of, top device enclosure portion4922 or device enclosure 4920. In FIG. 49B, magnet 4910 and shield 4940have detached from return plate 4950. Actuators 4972 have changedpositions but continued to connect structure 4970 to anchor 4974. Anchor4974 can be attached to, or formed as either part of, top deviceenclosure portion 4922 or device enclosure 4920.

5. NFC Circuitry in a Magnetic Alignment System

For various applications, it may be desirable to enable a device havinga magnetic alignment component to identify other devices that arebrought into alignment. In some embodiments where the devices support awireless charging standard that defines a communication protocol betweendevices, the devices can use that protocol to communicate. For example,the Qi standard for wireless power transfer defines a communicationprotocol that enables a power-receiving device (i.e., a device that hasan inductive coil to receive power transferred wirelessly) tocommunicate information to a power-transmitting device (i.e., a devicethat has an inductive coil to generate time-varying magnetic fields totransfer power wirelessly to another device) via a modulation scheme inthe inductive coils. The Qi communication protocol or similar protocolscan be used to communicate information such as device identification orcharging status or requests to increase or decrease power transfer fromthe power-receiving device to the power-transmitting device.

In some embodiments, a separate communication subsystem, such as aNear-Field Communication (NFC) subsystem can be provided to enableadditional communication, including device identification, from a tagcircuit located in one device to a reader circuit located in anotherdevice. (As used herein, “NFC” encompasses various protocols, includingknown standard protocols, that use near-field electromagnetic radiationto communicate data between antenna structures, e.g., coils of wire,that are in proximity to each other.) For example, each device that hasan annular magnetic alignment component can also have an NFC coil thatcan be disposed inboard of and concentric with the annular magneticalignment component. Where the device also has an inductive chargingcoil (which can be a transmitter coil or a receiver coil), the NFC coilcan be disposed in an annular gap between the inductive charging coiland the annular magnetic alignment component. In some embodiments, anNFC protocol can be used to allow a portable electronic device toidentify an accessory device when the respective magnetic alignmentcomponents of the portable electronic device and the accessory deviceare brought into alignment. For example, the NFC coil of a portableelectronic device can be coupled to an NFC reader circuit while the NFCcoil of an accessory device is coupled to an NFC tag circuit. Whendevices are brought into proximity, the NFC reader circuit of theportable electronic device can be activated to read the NFC tag of theaccessory device. In this manner, the portable electronic device canobtain information (e.g., device identification) from the accessorydevice.

In some embodiments, an NFC reader in a portable electronic device canbe triggered by detecting a change in a DC (or static) magnetic fieldwithin the portable electronic device that corresponds to a changeexpected when an accessory device having a complementary magneticalignment component is brought into alignment. When the expected changeis detected, the NFC reader can be activated to read an NFC tag in theother device, assuming the other device is present.

Examples of devices incorporating NFC circuitry and magnetic alignmentcomponents will now be described.

5.1. Portable Electronic Device with NFC Reader Circuitry

FIG. 50 shows a simplified back view of a portable electronic device5004 according to some embodiments. In this example, portable electronicdevice 5004 is a smart phone, but other devices having different formfactors can be substituted. Portable electronic device 5004 can includea wireless receiver coil assembly 5012. Wireless receiver coil assembly5012 can include a wireless receiver coil for inductive power transferfrom another device as well as AC magnetic and/or electric shield(s)disposed around some or all surfaces of the wireless receiver coil. Asecondary annular magnetic alignment component 5018 can be disposedaround wireless receiver coil assembly 5012. Secondary annular magneticalignment component 5018 can include a number of arcuate magnets 5028arranged in an annular configuration as shown. Each arcuate magnet 5028can have a magnetic orientation having a radial component, e.g.,radially inward or radially outward. (Examples of secondary annularmagnetic alignment components that can be included in portableelectronic device 5004 are described above in sections 1 and 3.) In someembodiments, secondary annular magnetic alignment component 5018 caninclude a gap 5001 (e.g., as described above with reference to FIG. 11),which can provide a space for electrical connections to wirelessreceiver coil assembly 5012 without adding to the thickness of portableelectronic device 5004. In some embodiments, portable electronic device5004 can also include a rotational alignment component 5024, which canbe implemented as described above in section 2. It should also beunderstood that portable electronic device 5004 may have an opaque rearhousing (not shown in FIG. 50) so that components such as wirelessreceiver coil assembly 5012 and secondary annular magnetic alignmentcomponent 5018 are not visible to a user.

According to some embodiments, an NFC coil 5060 can be disposed in anannular gap region between secondary annular magnetic alignmentcomponent 5018 and wireless receiver coil assembly 5012. NFC coil 5060can be, for example, a single turn of a double-stranded wire (which canbe made, e.g., of copper or other conductive material) having terminals5062 a, 5062 b connected to an NFC reader circuit (not shown). The NFCreader circuit, which can be of generally conventional design, can bedisposed on a main logic board of portable electronic device 5004, awayfrom secondary annular magnetic alignment component 5018. In someembodiments, positioning NFC coil 5060 in the annular gap region betweensecondary annular magnetic alignment component 5018 and wirelessreceiver coil assembly 5012 can allow NFC coil 5060 to be shielded fromAC electromagnetic fields generated in wireless receiver coil assembly5012 and from DC magnetic fields of secondary annular magnetic alignmentcomponent 5018. For instance, shielding can be provided by a combinationof AC shielding in receiver coil assembly 5012 and the closed-loopconfiguration of the arcuate magnet sections when coupled to a primarymagnetic alignment component (as described above in sections 1 and 3).

FIG. 51 shows an exploded view of a wireless charging and alignmentassembly 5100 for a portable electronic device incorporating an NFCreader according to some embodiments. Wireless charging and alignmentassembly 5100 can include wireless receiver coil assembly 5012 andsecondary annular magnetic alignment component 5018. Wireless receivercoil assembly 5012 and secondary annular magnetic alignment component5018 can be disposed on a layer 5101 of a pressure-sensitive adhesive(PSA). In some embodiments, an electric shield 5103 for wirelessreceiver coil assembly 5012 can be disposed on a portion of PSA layer5101, e.g., by depositing silver or other conductive material in anappropriate pattern. As is known in the art, electric shield 5103 canblock AC electric fields emitted by wireless transmitter coil 5012during operation while permitting AC magnetic fields to pass through.NFC coil 5060 can be disposed on PSA layer 5101 in the space between theouter edge of electric shield 5103 and the inner edge of secondaryannular magnetic alignment component 5018. NFC coil 5060 can be, forexample, a single-turn multi-stranded wire coil. An electromagneticshield assembly 5107 can be disposed over the distal surface of wirelessreceiver coil assembly 5012, NFC coil 5060, and secondary annularmagnetic alignment component 5018, thereby shielding other components ofportable electronic device 5004 from electromagnetic fields generated bywireless receiver coil assembly 5012 and NFC coil 5060.

FIG. 52 shows a simplified cross-section view of a portion of portableelectronic device 5004 of FIG. 50 incorporating assembly 5104 of FIG.51. As shown, wireless charging and alignment assembly 5100 can bedisposed between a front housing 5203 and a back housing 5205 ofportable electronic device 5001. In some embodiments, front housing 5203can be or incorporate a touchscreen display. Back housing 5205 can bemade of glass or plastic or any other material that does not interferewith wireless power or data transfer or with the magnetic fields of theannular alignment components such as secondary annular alignmentcomponent 5012. Assembly 5100 can be oriented with PSA layer 5101 andelectric shield 5103 toward back housing 5205 and shield assembly 5107toward front housing 5203 to enable wireless charging through backhousing 5205.

It should be understood that portable electronic device 5004 isillustrative and that variations and modifications are possible. Anassembly such as wireless charging and alignment assembly 5104 can beincorporated into a variety of electronic devices. In some embodiments,NFC coil 5060 and an NFC reader circuit coupled thereto are dedicated toidentifying accessory devices having a primary magnetic alignmentcomponent that is complementary to secondary magnetic alignmentcomponent 5018, and portable electronic device 5004 can include one ormore other NFC coils and associated circuitry for other applicationsinvolving NFC technology (such as point-of-sale payment transactions).

5.2. Wireless Charger Device with NFC Tag Circuit

In some embodiments, an NFC tag may be located in a device that includesa wireless charger and an annular alignment structure. The NFC tag canbe positioned and configured such that when the wireless charger deviceis aligned with a portable device having a complementary annularalignment structure and an NFC reader, the NFC tag is readable by theNFC reader of the portable electronic device.

FIG. 53 shows an exploded view of a wireless charger device 5302incorporating an NFC tag according to some embodiments, and FIG. 54Ashows a partial cross-section view of wireless charger device 5302according to some embodiments. As shown in FIG. 53, wireless chargerdevice 5302 can include an enclosure 5304, which can be made of plasticor metal (e.g., aluminum), and a charging surface 5306, which can bemade of silicone, plastic, glass, or other material that is permeable toAC and DC magnetic fields. Charging surface 5306 can be shaped to fitwithin a circular opening 5303 at the top of enclosure 5304.

A wireless transmitter coil assembly 5311 can be disposed withinenclosure 5304. Wireless transmitter coil assembly 5311 can include awireless transmitter coil 5312 for inductive power transfer to anotherdevice as well as AC magnetic and/or electric shield(s) 5313 disposedaround some or all surfaces of wireless transmitter coil 5312. Controlcircuitry 5314 (which can include, e.g., a logic board and/or powercircuitry) to control wireless transmitter coil 5312 can be disposed inthe center of coil 5312 and/or underneath coil 5312. In someembodiments, control circuitry 5314 can operate wireless transmittercoil 5312 in accordance with a wireless charging protocol such as the Qiprotocol or other protocols.

A primary annular magnetic alignment component 5316 can surroundwireless transmitter coil assembly 5311. Primary annular magneticalignment component 5316 can include a number of arcuate magnet sectionsarranged in an annular configuration as shown. Each arcuate magnetsection can include an inner arcuate region having a magnetic polarityoriented in a first axial direction, an outer arcuate region having amagnetic polarity oriented in a second axial direction opposite thefirst axial direction, and a central arcuate region that is notmagnetically polarized. (Examples are described above in sections 1 and3.) In some embodiments, the diameter and thickness of primary annularmagnetic alignment component 5316 is chosen such that arcuate magnetsections of primary annular magnetic alignment component 5316 fit undera lip 5309 at the top surface of enclosure 5304, as best seen in FIG.54A. For instance, each arcuate magnet section can be inserted intoposition under lip 5309, either before or after magnetizing the innerand outer regions. In some embodiments, primary annular magneticalignment component 5316 can have a gap 5336 between two adjacentarcuate magnet sections. Gap 5336 can be aligned with an opening 5307 ina side surface of enclosure 5304 to allow external wires to be connectedto wireless transmitter coil 5312 and/or control circuitry 5314.

A support ring subassembly 5340 can include an annular frame 5342 thatextends in the axial direction and a friction pad 5344 at the top edgeof frame 5342. Friction pad 5344 can be made of a material such assilicone or thermoplastic elastomers (TPE) such as thermoplasticurethane (TPU) and can provide support and protection for chargingsurface 5306. Frame 5342 can be made of a material such as polycarbonate(PC), glass-fiber reinforced polycarbonate (GFPC), or glass-fiberreinforced polyamide (GFPA). Frame 5342 can have an NFC coil 5364disposed thereon. For example, NFC coil 5364 can be a four-turn orfive-turn solenoidal coil made of copper wire or other conductive wirethat is wound onto frame 5342. NFC coil 5364 can be electricallyconnected to NFC tag circuitry (not shown) that can be part of controlcircuitry 5314. The relevant design principles of NFC circuits are wellunderstood in the art and a detailed description is omitted. Frame 5342can be inserted into a gap region 5317 between primary annular magneticalignment component 5316 and wireless transmitter coil assembly 5311. Insome embodiments, gap region 5317 is shielded by AC shield 5313 from ACelectromagnetic fields generated in wireless transmitter coil 5312 andis also shielded from DC magnetic fields of primary annular magneticalignment component 5316 by the closed-loop configuration of the arcuatemagnet sections.

FIG. 54B shows a partial cross-section view of another wireless chargerdevice 5402 according to some embodiments. Wireless charger device 5402can be generally similar to wireless charger device 5302 of FIGS. 53 and54A. For example, wireless charger device 5402 can include an enclosure5404, which can be made of plastic or metal (e.g., aluminum), and acharging surface 5406, which can be made of silicone, plastic, glass, orother material that is permeable to AC and DC magnetic fields. Chargingsurface 5406 can be shaped to fit within a circular opening at the topof enclosure 5404. A wireless transmitter coil assembly 5411 can bedisposed within enclosure 5304. Wireless transmitter coil assembly 5411be similar or identical to wireless transmitter coil assembly 5311.Control circuitry 5414, which can be similar or identical to controlcircuitry 5314 can be disposed, e.g., under coil assembly 5411.

A primary annular magnetic alignment component 5416 can surroundwireless transmitter coil assembly 5411. Primary annular magneticalignment component 5416 can be similar or identical to primary annularmagnetic alignment component 5316. In some embodiments, the diameter andthickness of primary annular magnetic alignment component 5416 is chosensuch that arcuate magnet sections of primary annular magnetic alignmentcomponent 5416 fit under a lip 5409 at the top surface of enclosure5404, similarly to the arrangement shown in FIG. 54A.

A support frame 5442 can extend between enclosure 5404 and top cap 5406.Support ring subassembly can be made of a material such as polycarbonate(PC), glass-fiber reinforced polycarbonate (GFPC), or glass-fiberreinforced polyamide (GFPA). Frame 5442 can have an NFC coil 5464disposed thereon on an upper surface thereof. For example, NFC coil 5464can be a four-turn or five-turn planar coil made of concentric turns ofcopper wire or other conductive wire that is wound onto frame 5442.(Alternatively, a solenoidal wound NFC coil similar to coil 5364 can beused.) NFC coil 5464 can be electrically connected to NFC tag circuitry(not shown) that can be part of control circuitry 5414. Frame 5442 canbe inserted into a gap region between primary annular magnetic alignmentcomponent 5416 and wireless transmitter coil assembly 5411. In someembodiments, gap region 5417 is shielded by AC shield 5413 from ACelectromagnetic fields generated in wireless transmitter coil 5412 andis also shielded from DC magnetic fields of primary annular magneticalignment component 5416 by the closed-loop configuration of the arcuatemagnet sections.

5.3. Accessory Device with NFC Tag Circuit

As described above in section 3, an accessory device such as a case fora mobile phone may include an auxiliary magnetic alignment component,with or without a wireless charging coil. The auxiliary magneticalignment component can act as a “repeater” to support the use of aprimary magnetic alignment component and a secondary alignment componentto align the wireless charging transmitter coil of a charger device withthe wireless charging receiver coil of a portable electronic devicewhile the portable electronic device is attached to (e.g., insertedinto) the accessory device.

In some embodiments, an NFC tag circuit and coil may be incorporatedinto an accessory device having an auxiliary magnetic alignmentcomponent. The NFC tag can be read by the NFC reader of the portableelectronic device (e.g., using NFC coil 5060 and associated NFC readercircuit of portable electronic device 5004 as described above), allowingthe portable electronic device to identify the accessory device when theaccessory device is in proximity and aligned with the portableelectronic device.

FIG. 55 shows an example of an accessory device 5500 incorporating anauxiliary alignment component with an NFC tag circuit and coil accordingto some embodiments. Accessory device 5500 can be, for example, a casefor portable electronic device 5004 (which can be, e.g., a smart phone).Accessory device 5500 can be shaped as a tray, sleeve, or other formfactor as desired that covers and protects one or more surfaces ofportable electronic device 5004. In particular, accessory device 5500can have a rear (or back) panel 5502 that covers the rear surface ofportable electronic device 5004. It should be understood that rear panel5502 need not cover the entire rear surface of portable electronicdevice 5004; for example, a cutout area 5503 can be provided to expose arear camera lens of portable electronic device 5004.

Rear surface 5502 can include an auxiliary annular magnetic alignmentcomponent 5570. Auxiliary annular magnetic alignment component 5570 caninclude a number of arcuate magnets 5572 arranged in an annularconfiguration as shown. Each arcuate magnet 5572 can include an innerarcuate region having a magnetic polarity oriented in a first axialdirection, an outer arcuate region having a magnetic polarity orientedin a second axial direction opposite the first axial direction, and acentral arcuate region that is not magnetically polarized. (Examples aredescribed above in section 3.) Auxiliary annular magnetic alignmentcomponent 5570 can align with secondary annular magnetic alignmentcomponent 5018 of electronic device 5002.

An NFC tag circuit assembly 5566 can be disposed inboard of auxiliaryannular magnetic alignment component 5316. In some embodiments, all orpart of region 5505 of rear surface 5502, inboard of NFC tag circuitassembly 5566, can be a cutout area. FIG. 56 shows a more detailed viewof NFC tag circuit assembly 5566 according to some embodiments. NFC tagcircuit assembly 5566 can include a printed circuit on a printed circuitboard (PCB) 5602 (which can be, e.g., a flexible PCB) having a circularouter perimeter that fits within the inner diameter of auxiliary annularmagnetic alignment component 5572 as shown in FIG. 55. In someembodiments, PCB 5602 can be a disc. In other embodiments, PCB 5602 canhave a central opening 5603, which can have various shapes. In someembodiments, the size of opening 5603 can be based on the area needed toaccommodate NFC tag circuit components.

An NFC antenna coil 5604 can be disposed on a peripheral portion of PCB5602 NFC antenna coil 5604 can be an etched planar coil on PCB 5602 andcan include, e.g., four or five turns of copper or other electricallyconductive material. NFC antenna coil 5604 can be coupled to an NFC tagchip 5606 (shown in inset 5620) and capacitors 5608, which can bedisposed on PCB 5602 inward of NFC antenna coil 5604. NFC tag chip 5606can be, for example, a passively powered NFC tag chip or other passivelypowered NFC tag circuit that is compatible with the NFC reader of aportable electronic device. Capacitors 5608 can be, for example,multilayer ceramic capacitors that support operation of NFC tag chip5606. A particular selection and configuration of supporting capacitorsdepends on the NFC tag chip and coil configuration; the relevant designprinciples of NFC circuits are well understood in the art and a detaileddescription is omitted.

In general, NFC tag circuit 5606 and capacitors 5608 have height thatextends above PCB 5602. To provide a flat profile for NFC tag circuitassembly 5566, additional tape layers may be added to PCB 5602. FIG. 57shows an exploded view of NFC tag circuit assembly 5566 including tapelayers stacked on PCB 5602 to provide uniform height according to someembodiments. PCB 5602 is shown at the bottom. Tape layers 5702 and 5703can each be layers of polyester tape (PET) with a pressure-sensitiveadhesive (PSA), and each layer can be, e.g., about 150 μm thick. Asshown, each of tape layers 5702 and 5703 can be shaped to match theshape of PCB 5602 and may have holes 5705 therethrough to accommodatethe height of NFC tag chip 5606 and capacitors 5608. The sum of thethicknesses of tape layers 5702 and 5703 can equal or exceed the heightof NFC tag chip 5606 and capacitors 5608. (While two tape layers areshown, it should be understood that any number of tape layers can beused depending on the thickness of the tape layers and the height of theNFC circuit components.) Top layer 5710 can be, e.g., PSA, and need nothave holes therethrough. In some embodiments, the total height of NFCtag circuit assembly 5566 can be less than half a millimeter.

FIG. 58 shows a partial cross section view of charge-through accessory5500 of FIG. 55 incorporating NFC tag circuit assembly 5566 andauxiliary alignment component 5570 according to some embodiments.Charge-through accessory 5500 can be, e.g., a tray or other case for aportable electronic device, and the portion shown in FIG. 58 can formpart of rear panel 5502 of charge-through accessory 5500. (A backsurface of a portable electronic device can be positioned adjacent tosurface 5801.) Rear panel 5502 can have an internal structure with aninner layer 5804 and an outer layer 5806, which can be made of orincorporate silicone, plastic, leather, or other materials that arepermeable to DC and AC magnetic fields. In some embodiments, inner layer5804 and outer layer 5806 provide flat surfaces for rear panel 5502. Acentral layer 5808 can be disposed between inner layer 5804 and outerlayer 5806. Central layer 5808 can define a recess region 5809 toaccommodate NFC tag circuit assembly 5566 and an auxiliary annularmagnetic alignment component 5870. Auxiliary annular magnetic alignmentcomponent 5870 can be similar or identical to auxiliary annular magneticalignment component 5570 or other examples described above. As shown,the height of NFC tag circuit assembly 5566 can be less than or equal tothe height of auxiliary alignment component 5870, and recess region 5809can be shaped appropriately.

As shown in FIG. 56, NFC tag circuit assembly 5566 extends inward fromNFC coil 5604 to provide space for NFC tag chip 5606 and capacitors5608. Since both NFC tag circuit assembly 5566 and auxiliary annularalignment component 5570 include opaque elements, it is not possible tomake all portions of rear panel 5502 of accessory 5500 transparent toreveal the rear surface of a portable electronic device held inaccessory 5500. For esthetic purposes it may be desirable to minimizethe width of the non-transparent region of rear panel 5502.

FIG. 59 shows an example of another accessory device 5900 having anauxiliary alignment component with an NFC tag circuit and coil accordingto some embodiments. Accessory device 5900 can be, for example, a casefor portable electronic device 5004 (which can be, e.g., a smart phone).Like accessory device 5500 described above, accessory device 5900 can beshaped as a tray, sleeve, or other form factor as desired that coversand protects one or more surfaces of portable electronic device 5004. Inparticular, accessory device 5900 can have a rear (or back) panel 5902that covers the rear surface of portable electronic device 5004. Itshould be understood that rear panel 5902 need not cover the entire rearsurface of portable electronic device 5004; for example, a cutout area5903 can be provided to expose a rear camera lens of portable electronicdevice 5004.

Rear panel 5902 can include an auxiliary annular magnetic alignmentcomponent 5970 and an NFC tag circuit assembly 5966. Auxiliary annularmagnetic alignment component 5970 can include a number of arcuatemagnets 5972 arranged in an annular configuration as shown. Each arcuatemagnet 5972 can include an inner arcuate region having a magneticpolarity oriented in a first axial direction, an outer arcuate regionhaving a magnetic polarity oriented in a second axial direction oppositethe first axial direction, and a central arcuate region that is notmagnetically polarized. (Examples are described above with reference tosection 3.) Auxiliary annular magnetic alignment component 5970 canalign with secondary annular magnetic alignment component 5018 ofportable electronic device 5002.

FIG. 60 shows an enlarged view of auxiliary annular magnetic alignmentcomponent 5970 and NFC tag circuit assembly 5966 of FIG. 59 according tosome embodiments. Annular alignment component 5970 can include a numberof arcuate magnets 5972 arranged in an annular configuration, with gaps6001 between selected pairs of adjacent magnets 5972. In the exampleshown, each gap 6001 can be created by omitting an arcuate magnet 5972.Other techniques, examples of which are described above, can be used tocreate gaps 6001. Gaps 6001 can accommodate components of NFC tagcircuit assembly 5966, which can reduce the inward extension of NFC tagcircuit assembly 5966 and increase the component-free area in centerregion 6003.

NFC tag circuit assembly 5966 can include a printed circuit on a PCB6002 (e.g., a flexible PCB) having a circular inner perimeter and acircular outer perimeter with projections 6022 that extend into gaps6001 in annular magnetic alignment component 5970. An NFC antenna coil6004 can be disposed on the circular portion of PCB 6002. NFC antennacoil 6004 can be an etched planar coil on PCB 6002 or a wound wire coiland can include, e.g., four or five turns of copper or otherelectrically conductive material. NFC antenna coil 6004 can be coupledto an NFC tag chip 6006 and capacitors 6008, each of which can bedisposed on a different one of projections 6022 of PCB 6002 betweenmagnets 5972 of annular alignment component 5970. NFC tag chip 6006 andcapacitors 6008 can include standard NFC tag circuit components asdescribed above. As can be seen, PCB 6002 can add less to the width ofauxiliary annular alignment component 5970 than PCB 5602 of FIG. 56. Thenarrower opaque assembly may be esthetically desirable in instanceswhere rear panel 5902 of accessory 5900 is generally made of transparentmaterial and/or in instances where the region 6003 inboard of NFC tagcircuit assembly 5966 provides a hole through rear panel 5902.

FIG. 61 shows an exploded view of NFC tag circuit assembly 5966according to some embodiments. PCB 6002 can have a layer of PSAunderneath and a tape layer 6104 on top. Tape layer 6104 can be a layerof PET with a PSA. In some embodiments, magnets 5972 of annularalignment component 5960 provide uniform height, and tape layer 6104 canoverlie and encapsulate NFC tag chip 6006 and capacitors 6008.

As described above, a portable electronic device can include an annularmagnetic alignment component and an NFC reader circuit, while eachaccessory device can include an annular magnetic alignment component andan NFC tag circuit. The NFC reader and tag circuits can be arranged suchthat, when the portable electronic device is brought into alignment withone or more accessory devices, the NFC reader circuit in the portableelectronic device is brought into near enough proximity to the NFC tagcircuit(s) of the accessory device(s) to allow the NFC reader circuit toread the NFC tag(s), thereby allowing the portable electronic device toidentify the accessory device(s). The NFC tag circuits can be passivetags that are energized by the near-field of the NFC reader coil, sothat an accessory device incorporating an NFC tag circuit need not haveits own power supply.

FIG. 62 shows a simplified partial cross-section view of a system 6200that includes a wireless charger device 6202, a portable electronicdevice 6204, and an accessory device 6220 according to some embodiments.Portable electronic device 6204 includes a secondary annular magneticalignment component 6218 (which can be similar or identical to secondarymagnetic alignment component 5018), a wireless receiver coil assembly6212 (which can be similar or identical to wireless receiver coilassembly 5012 described above), and NFC coil 6260 (which can be similarto NFC coil 5060 described above) that connects to an NFC reader circuit(not shown). NFC coil 6260 can be disposed between secondary annularmagnetic alignment component 6218 and wireless receiver coil assembly6212.

Wireless charger device 6202 includes a primary annular magneticalignment component 6216 (which can be similar or identical to primaryannular magnetic alignment component 5316 described above), a wirelesstransmitter coil assembly 6211 (which can be similar to wirelesstransmitter coil assembly 5311 described above), and NFC tag circuitassembly 6240, which can be similar to support ring subassembly 5340described above and can include NFC coil 6264 and an associated NFC tagcircuit (not shown). NFC coil 6264 can be disposed between primaryannular alignment component 6216 and wireless transmitter coil assembly6211.

Accessory device 6220 includes an auxiliary annular magnetic alignmentcomponent 6270 (which can be similar or identical to auxiliary annularmagnetic alignment component 5570 described above) and an NFC tagcircuit assembly 6266, which can be similar or identical to NFC tagcircuit assembly 5566 or NFC tag circuit assembly 5966 described above.NFC tag circuit assembly 6266 can be disposed inboard of auxiliaryannular magnetic alignment component 6270.

Wireless charger device 6202 includes a primary annular magneticalignment component 6216 (which can be similar or identical to primaryannular magnetic alignment component 5316 described above), a wirelesstransmitter coil assembly 6211 (which can be similar to wirelesstransmitter coil assembly 5311 described above), and NFC tag circuitassembly 6240, which can be similar to support ring subassembly 5340described above and can include NFC coil 6264 and an associated NFC tagcircuit (not shown). NFC coil 6264 can be disposed between primaryannular alignment component 6216 and wireless transmitter coil assembly6211.

Accessory device 6220 includes an auxiliary annular magnetic alignmentcomponent 6270 (which can be similar or identical to auxiliary annularmagnetic alignment component 5570 described above) and an NFC tagcircuit assembly 6266, which can be similar or identical to NFC tagcircuit assembly 5566 or NFC tag circuit assembly 5966 described above.NFC tag circuit assembly 6266 can be disposed inboard of auxiliaryannular magnetic alignment component 6270.

As shown in FIG. 62, NFC coil 6260 of portable electronic device 6204 isin proximity to NFC coil 6266 of accessory device 6220 and to NFC coil6264 of wireless charger device 6202. Accordingly, portable electronicdevice 6204 can read the NFC tags of both accessory device 6220 andwireless charger device 6202 whenever either is attached. It should beunderstood that at different times, accessory device 6220 may be presentwhile wireless charger device 6202 is absent, or wireless charger device6202 may be present while accessory device 6220 is absent. At any giventime, portable electronic device 6204 can read the NFC tag of any devicethat happens to be present and aligned with secondary annular magneticalignment component 6216. In some embodiments, portable electronicdevice 6204 can include a low-power proximity sensor that detects whenan accessory device or wireless charger device is brought intoalignment, and portable electronic device 6204 can activate its NFCreader circuit in response to a proximity detection event. Specificexamples are described below.

In the example of FIG. 62, accessory device 6220 has its NFC coil 6266disposed inboard of secondary annular alignment component 6270. In somealternative embodiments, an NFC coil of an accessory device can bedisposed outboard of the auxiliary annular alignment component. FIG. 63shows an example of an accessory device 6300 having an auxiliaryalignment component with an NFC tag circuit and coil according to someembodiments. Accessory device 6300 can be, for example, a case forportable electronic device 5004 (which can be, e.g., a smart phone).Like accessory devices 5500 and 5900 described above, accessory device6300 can be shaped as a tray, sleeve, or other form factor as desiredthat covers and protects one or more surfaces of portable electronicdevice 5004. In particular, accessory device 6300 can have a rear (orback) panel 6302 that covers the rear surface of portable electronicdevice 5004. It should be understood that rear panel 6302 need not coverthe entire rear surface of portable electronic device 5004; for example,a cutout area 6303 can be provided to expose a rear camera lens ofportable electronic device 5004.

Rear panel 6302 can include an auxiliary annular magnetic alignmentcomponent 6370 and an NFC tag circuit assembly 6366. Auxiliary annularmagnetic alignment component 6370 can include a number of arcuatemagnets 6372 arranged in an annular configuration as shown. Each arcuatemagnet 6372 can include an inner arcuate region having a magneticpolarity oriented in a first axial direction, an outer arcuate regionhaving a magnetic polarity oriented in a second axial direction oppositethe first axial direction, and a central arcuate region that is notmagnetically polarized. (Examples are described above in section 3.)Auxiliary annular magnetic alignment component 6370 can align withsecondary annular magnetic alignment component 5018 of portableelectronic device 5002. NFC tag circuit assembly 6366 can be disposedoutboard (i.e., outside the outer perimeter) of auxiliary annularmagnetic alignment component 6370. Although not shown in detail, itshould be understood that NFC tag circuit assembly 6366 can beconstructed similarly to NFC tag circuit assembly 5566 described above.For instance, NFC tag circuit assembly 6366 can include a ring-shapedPCB with an etched NFC coil. A peripheral extension of the PCB (e.g., atregion 6371) can provide an area for mounting of NFC tag circuitcomponents (e.g., an NFC tag chip and capacitors).

FIG. 64 shows a system 6400 that includes a wireless charger device6402, a portable electronic device 6404, and an accessory device 6420according to some embodiments. Portable electronic device 6404 includesa secondary annular magnetic alignment component 6418 (which can besimilar or identical to secondary magnetic alignment component 5018), awireless receiver coil assembly 6412 (which can be similar or identicalto wireless receiver coil assembly 5012 described above), and NFC coil6460 (which can be similar to NFC coil 5060 described above) thatconnects to an NFC reader circuit (not shown). NFC coil 6460 can bedisposed between secondary annular magnetic alignment component 6418 andwireless receiver coil assembly 6412.

Wireless charger device 6402 includes a primary annular magneticalignment component 6416 (which can be similar or identical to primaryannular magnetic alignment component 5316 described above), a wirelesstransmitter coil assembly 6411 (which can be similar to wirelesstransmitter coil assembly 5511 described above), and NFC tag circuitassembly 6440, which can be similar to support ring subassembly 5540described above and can include NFC coil 6464 and an associated NFC tagcircuit (not shown). NFC coil 6464 can be disposed between primaryannular alignment component 6416 and wireless transmitter coil assembly6411.

Accessory device 6420 includes an auxiliary annular magnetic alignmentcomponent 6470 (which can be similar or identical to auxiliary annularmagnetic alignment component 5570 described above) and an NFC tagcircuit assembly 6466, which can be similar or identical to NFC tagcircuit assembly 6366 described above; in particular, NFC tag circuitassembly 6466 can be disposed outboard of auxiliary annular magneticalignment component 6470.

As shown in FIG. 64, NFC coil 6460 of portable electronic device 6404 isin proximity to NFC coil 6466 of accessory device 6420 and to NFC coil6464 of wireless charger device 6402. Accordingly, portable electronicdevice 6404 can read the NFC tags of both accessory device 6420 andwireless charger device 6402 whenever either is attached. It should beunderstood that at different times, accessory device 6420 may be presentwhile wireless charger device 6402 is absent, or wireless charger device6402 may be present while accessory device 6420 is absent. At any giventime, portable electronic device 6404 can read the NFC tag of any devicethat happens to be present and aligned with secondary annular magneticalignment component 6416. In some embodiments, portable electronicdevice 6404 can include a low-power proximity sensor that detects whenan accessory device or wireless charger device is brought intoalignment, and portable electronic device 6204 can activate its NFCreader circuit in response to a proximity detection event. Specificexamples are described below.

5.4. Proximity Detection to Trigger NFC Reader Circuit

Referring again to FIG. 50, as noted above, it may be desirable toselectively trigger the NFC reader circuit in portable electronic device5004 when a compatible accessory comes into proximity with portableelectronic device 5004. Proximity-based triggering of the NFC readercircuit can allow considerable power savings as compared to periodicallypolling the NFC reader circuit and can also avoid the need for the userto take any action to trigger the NFC reader circuit, other thanbringing devices into proximity.

In some embodiments, an electromagnetic sensor can be used to detectwhen a device having an annular alignment component complementary tosecondary annular alignment component 5018 is brought into alignment.For example, a three-axis magnetometer 5080 can be positioned within therear enclosure of portable electronic device 5004 in an area nearsecondary annular alignment component 5018 and coupled to control logiclocated in a main logic board of portable electronic device 5004.Magnetometer 5080 can be a low-power component that can be periodicallypolled to measure a magnetic field at the location of magnetometer 5080.In particular, based on periodic polling, a “baseline” magnetic fieldcan be established, which can include a contribution from secondaryannular alignment component 5018 and from any other devices that arecurrently aligned with secondary annular alignment component 5018. Whena device having an annular magnetic alignment component complementary tosecondary annular magnetic alignment component 5018 (e.g., wirelesscharger device 5302 or accessory device 5500) is brought into alignmentwith secondary annular magnetic alignment component 5018, the magneticfield at the location of magnetometer 5080 changes abruptly relative tothe baseline in a specific and predictable manner. Accordingly, a changein the measured magnetic field (relative to baseline) having aparticular magnitude can be used to detect when a device with acomplementary magnetic alignment component is brought into proximitywith portable electronic device 5004. In some embodiments, the changecan be defined as a three-dimensional vector, and detection of a devicebeing brought into proximity can be triggered based on changes inmagnitude and/or direction of the field measured by magnetometer 5080.Further, aligning different types of devices may result in differentchanges in the magnetic field measured by magnetometer 5080. Forinstance, as shown in FIG. 62, primary annular magnetic alignmentcomponent 6216 may be thicker than auxiliary annular magnetic alignmentcomponent 6270, and this difference may result in different effects onthe magnetic field measured by magnetometer 5080. In addition, thechange in magnetic field measured by magnetometer 5018 when a wirelesscharger device (e.g., wireless charger device 5302) is brought intoalignment while portable electronic device 5004 is already aligned withan accessory (e.g., accessory 5500) may be different from the changemeasured when a wireless charger device (e.g., wireless charger device5302) is brought into alignment while no accessory is present. Controllogic (e.g., logic circuits located on a main logic board of portableelectronic device 5500) can periodically (e.g., every few millisecondsor a few times per second) monitor changes in the magnetic fielddetected by magnetometer 5018 and can determine, based on the changes,whether a device having a complementary magnetic alignment component hasbeen brought into proximity (or, if one such device is already known tobe present, whether another such device has also been brought intoproximity). In response to determining that a device has been broughtinto proximity, the control logic can trigger operation of NFC coil 5060and the associated NFC reader circuit to read an NFC tag that may bepresent in a newly-proximate device. It should be understood thatdetachment (or removal from proximity) of an active or passive accessorydevice can also be detected by detecting changes in the magnetic fieldmeasured by magnetometer 5080.

In some embodiments, based on the information in the NFC tag of thealigned device, portable electronic device 5004 may modify some aspectof its behavior. In some embodiments, an NFC tag in an accessory devicemay indicate a property of the accessory device, such as its color ordesign style. Portable electronic device 5004 can modify its colorscheme or other elements of its user interface accordingly. Forinstance, portable electronic device 5004 may generate a transient colorwash effect on the screen in a color matching the color of the accessorydevice. As another example, the accessory device may be a sleeve havingan opaque front panel, in which a window is provided to expose a portionof the display of portable electronic device 5004, and when portableelectronic device is aligned inside the sleeve, portable electronicdevice 5004 can switch to a mode that displays specific content (e.g.,current time or notifications) on the portion of the display that alignswith the window. In some embodiments, the accessory identification mayprovide context information about the environment in which the accessoryis present: for example, a docking accessory may be located in a vehicleor positioned in a particular room, and portable electronic device 5004can modify its behavior based on the context information (e.g., byswitching to an in-vehicle display mode when docked in a vehicle dock).As yet another example, the accessory may be a detachable pack; whenportable electronic device 5004 detects (e.g., based on magnetometersignals) that the accessory has been attached or detached, portableelectronic device 5004 can store information about the attachment ordetachment event (e.g., location information indicating where portableelectronic device 5004 was when attachment or detachment occurred). Insome embodiments, portable electronic device 5004 can provide the storedinformation to a user (e.g., providing location information indicatingwhere detachment occurred to assist the user in locating the detachedaccessory). As a further example, accessory identification may result inportable electronic device 5004 launching a particular app associatedwith the accessory or unlocking certain functionality of a particularapp. It should be understood from these examples that many aspects ofdevice behavior can be modified in response to information received froman NFC tag. As a still further example, if an accessory is identifiedvia its NFC tag as a battery pack but portable electronic device 5004 isunable to draw power from the accessory, portable electronic device 5004can determine that the battery is dead and can alert the useraccordingly. It should be understood that many aspects of behavior of aportable electronic device can be modified in response to detecting thata particular accessory has become attached or detached.

FIG. 65 shows a flow diagram of a process 6500 that can be implementedin portable electronic device 5004 according to some embodiments. Insome embodiments, process 6500 can be performed iteratively whileportable electronic device 5004 is powered on. At block 6502, process6500 can determine a baseline magnetic field, e.g., using magnetometer5080. At block 6504, process 6500 can continue to monitor signals frommagnetometer 5080 until a change in magnetic field is detected. At block6506, process 6500 can determine whether the change in magnetic fieldmatches a magnitude and direction of change associated with alignment ofa complementary magnetic alignment component. If not, then the baselinemagnetic field can be updated at block 6502. If, at block 6506, thechange in magnetic field matches a magnitude and direction of changeassociated with alignment of a complementary alignment component, thenat block 6508, process 6500 can activate the NFC reader circuitryassociated with NFC coil 5060 to read an NFC tag of an aligned device.In some embodiments, NFC tags associated with different types of devices(e.g., a passive accessory versus an active accessory such as a wirelesscharger) are tuned to respond to different stimulating signals from theNFC reader circuitry, and information about the particular change inmagnetic field can be used to determine a particular stimulating signalto be generated by the NFC reader circuitry. At block 6510, process 6500can receive identification information read from the NFC tag. At block6512, process 6500 can modify a behavior of portable electronic device5004 based on the identification information, for example, generating acolor wash effect as described above. After block 6512, process 6500 canoptionally return to block 6502 to provide continuous monitoring ofmagnetometer 5080. It should be understood that process 6500 isillustrative and that other processes may be performed in addition to orinstead of process 6500.

It will be appreciated that the NFC tag and NFC reader circuitsdescribed above are illustrative and that variations and modificationsare possible. For example, coil designs can be modified by replacingwound wire coils with etched coils (or vice versa) and solenoidal coilswith flat coils (or vice versa). “Wound wire” coils can be made using avariety of techniques, including by winding a wire, by stamping a coilfrom a copper sheet and molding plastic over the stamped part, or byusing a needle dispenser to deposit wire on a plastic part; the wire canbe heated so that it embeds into the softened plastic. Etched coils canbe made by coating a surface with metal and etching away the unwantedmetal. The number of turns in various NFC coils can be modified for aparticular application. The choice of wound wire coils or etched coilsfor a particular device may depend on various design considerations. Forinstance, in devices that have an internal logic board, a wound wire NFCcoil can terminate to the logic board; where a logic board is absent, anetched coil may simplify termination of the coil. Other designconsiderations may include the Q factor of the coil (a wound coil canprovide higher Q in a smaller space) and/or ease of assembly.

Further, where a device that has an NFC tag circuit also has activecircuitry (such as wireless charger devices that have active circuitryto control charging behavior), the NFC tag circuit is not limited tobeing a passive tag; an active NFC tag circuit can be provided to enabletwo-way communication with a compatible portable electronic device. Forexample, active NFC circuits in a portable electronic device and awireless charger device can be used to support delivery of firmwareupdates to the wireless charger device.

Proximity-detection techniques can also be varied. For example, adifferent type of magnetometer (e.g., a single-axis magnetometer) can beused, or multiple magnetometers in different locations relative to themagnetic alignment components can be used. In some embodiments, a Halleffect sensor can be used instead of a magnetometer, although falsepositives may increase because a Hall effect sensor can generally onlyindicate a change or no-change rather than measuring a magnitude ordirection of change. It should also be understood that proximitydetection as described herein can be used for other purposes in additionto or instead of triggering an NFC reader circuit.

6. Example Devices Incorporating Magnetic Alignment Components

6.1. Wireless Charger Devices

Examples of wireless charger devices (or wireless chargers)incorporating annular magnetic alignment components are described above,e.g., with reference to FIGS. 13 and 53-54. As another example, FIG. 66shows an exploded view of a wireless charger device 6600 according tosome embodiments, and FIG. 67 shows a simplified partial cross-sectionview of wireless charger device 6600 according to some embodiments.Wireless charger device 6600 is similar to wireless charger device 1300described above and can incorporate a magnetic alignment component(e.g., a primary annular alignment component as described above) as wellas other features related to optimizing charging performance.

Wireless charger device 6600 can have a two-piece puck-shaped housingthat includes a cap 6602 and an enclosure 6606. Cap 6602, which providesa charging surface for wireless charger device 6600, can be made ofpolycarbonate or other plastic and coated on the proximal side (the topside in FIGS. 66 and 67) with soft-touch silicone or the like to providea durable surface. Other materials that are permeable to electromagneticfields can also be used. In some embodiments, the proximal surface oftop cap 6602 can be a low-friction surface (e.g., textured silicone), aswireless charger device 6600 can rely on magnetic forces rather thanfriction for maintaining alignment with a device to be charged.Enclosure 6606 can be made of aluminum, other electrically conductivematerials, or a plastic material. As best seen in FIG. 67, enclosure6606 can include a rear housing 6601, a sidewall 6603, and anoverhanging lip 6605 with a recessed ledge 6609 on which top cap 6602can rest. Top cap 6602 can have a small offset (e.g., 150 μm) above theupper surface of lip 6605, to prevent ferrous particles that may stickto lip 6605 from scratching the surface of a device placed in proximityto top cap 6602. In some embodiments, top cap 6602 can be sealed torecessed ledge 6609 using a suitable sealing material. Enclosure 6606can include an opening 6607 through sidewall 6603 to allow electricalconduits (e.g., wires) to be connected between the interior and exteriorof wireless charger device 6600.

An annular magnetic alignment component 6616 can include arcuate magnets6626 disposed on an annular DC shield 6614. Magnetic alignment component6616 can be an implementation of any of the primary annular alignmentcomponents described above. For example, each arcuate magnet 6626 canhave a quad-pole configuration with an inner arcuate region havingmagnetic polarity oriented in a first axial direction, an outer arcuateregion having magnetic polarity oriented in a second axial directionopposite the first direction, and a central non-magnetized regionbetween the inner arcuate region and the outer arcuate region. In someembodiments, DC shield 6614 can be segmented, e.g., into four arcuatesegments, and each segment of DC shield 6614 can have one or morearcuate magnets 6626 mounted thereon. The segments can be individuallyinserted into enclosure 6606 such that each segment fits under lip 6605and the segments are adjacent to each other (either abutting or havingsmall gaps to accommodate manufacturing tolerances). Fiducial surfacefeatures may be provided on the inner surface of enclosure 6606 tofacilitate correct positioning of each segment. A gap 6617 that is largeenough to accommodate electrical connection paths can be providedbetween two adjacent segments of annular magnetic alignment component6616, and gap 6617 can be aligned with opening 6607 in enclosure 6606.To maximize the magnetic alignment force exerted by annular magneticalignment component 6616 on a portable electronic device placed adjacentto the top surface of cap 6603, annular magnetic alignment component6616 can be positioned such that the proximal surfaces of magnets 6626are adjacent to (e.g., in contact with) the inner surface of lip 6605.In some embodiments, DC shield 6614 can rest on the inner surface ofrear housing 6601 of enclosure 6606, and annular magnetic alignmentcomponent 6616 can extend to the full height of the inner side ofsidewall 6603 so that the proximal surfaces of magnets 6626 are adjacentto the inner surface of lip 6605. In other embodiments, annular magneticalignment component 6616 can be shorter than the inner side of sidewall6603, and a spacer 6615 (shown in FIG. 67) can be positioned between DCshield 6614 and rear housing 6601 so that magnets 6626 are adjacent tothe underside of lip 6605. In any event, adhesives (not shown) can beused to hold magnetic alignment component 6616 (or sectors thereof) inposition.

A charging coil assembly 6612 can include a coil 6620, an electricshield 6622, electromagnetic shields 6626, 6628, and a shim 6624. Coil6620 can be a coil of wound copper wire with terminals toward the centerof the coil, having a proximal surface oriented toward top cap 6601 andan opposing distal surface. An upper electromagnetic shield 6626 and alower electromagnetic shield 6628 can be made of ferrimagnetic material(e.g., MnZn). Upper electromagnetic shield 6626, which provides primaryfield shaping for coil 6620, can be contoured to surround the distalsurface and outer sides of coil 6620 and can have a slit 6627 to providespace for a wire extending from the outer edge of coil 6620 to theterminal point in the center region of coil 6620. Lower electromagneticshield 6628, which acts as a spacer for a main logic board 6632, can beflat and shaped to underlie coil 6620 with a trench to accommodate thewire extending from the outer edge of coil 6620 to the terminal point inthe center region of coil 6620. Lower electromagnetic shield 6628 can begrounded to enclosure 6606. In some alternative embodiments, lowerelectromagnetic shield 6628 can be replaced with a plastic spacer. Inother alternative embodiments, upper electromagnetic shield 6626 andlower magnetic shield 6628 can be formed from a single piece of ferritematerial. An electric shield 6622 can be positioned over the proximalsurface of coil 6620. Electric shield 6622 can be made of a flexibleprinted circuit board patterned with conductive material to blockelectric fields while being permeable to magnetic fields. Electricshield 6622 can include peripheral conductive protrusions that can be incontact with enclosure 6606 to provide grounding. Shim 6624 can be madeof a polycarbonate material and can be used to provide a uniform heightacross the proximal surface of charging coil assembly 6612, helping tosupport cap 6602.

A support ring subassembly 6640 can be positioned between annularmagnetic alignment component 6616 and coil assembly 6612 (as best seenin FIG. 67). Support ring subassembly 6640 can be an implementation ofsupport ring subassembly 5340 described above with reference to FIGS. 53and 54. For example, support ring subassembly 6640 can include anannular frame 6642 and an NFC coil 6664. Annular frame 6642 can be made,e.g., of glass-reinforced polycarbonate or other plastics. NFC coil 6664can be, e.g., a wound copper coil of 4 or 5 turns. NFC coil 6664 can becoupled to NFC tag circuitry that can be disposed on main logic board6632. NFC coil 6664 and associated tag circuitry can be used for deviceidentification as described in section 5 above.

Main logic board 6632 can be disposed on a central portion of rearhousing 6601 of enclosure 6606 and secured in place with apressure-sensitive adhesive 6634. Main logic board 6632 can includecontact pads for connecting to external wires through opening 6607 ofenclosure 6606 and additional ground contacts for grounding enclosure6606 and electric shield 6622. Main logic board 6632 can also includecircuit components to control operation of coil 6620. For example,depending on implementation, main logic board 6632 can be coupled toreceive DC power via the contact pads and can include power circuitryfor driving coil 6620 (e.g., a boost circuit and an inverter). Inaddition or instead, main logic board 6632 can include logic circuits(e.g., a microcontroller, ASIC, FPGA, or the like) to monitor thebehavior of coil 6620 and to control current supplied to coil 6620 basedon the monitoring. Examples of control logic for operating a wirelesscharging coil are known in the art; for instance, the logic circuits canimplement functionality confirming to the Qi standard for wirelesscharging. In some embodiments, main logic board 6632 can also includeNFC tag circuit components coupled to NFC coil 6664. In someembodiments, logic circuits, power circuits, and/or NFC tag circuits canbe implemented as integrated circuits mounted on main logic board 6632,and the integrated circuits may be covered by shield cans to avoidelectrical interference.

In some embodiments, thermal performance of wireless charger device 6600can be improved by placing some or all of the power circuitry at alocation external to enclosure 6606. For example, FIG. 68 shows anexploded view of a cable assembly 6800 with incorporated power circuitrythat can be connected to wireless charger device 6600 according to someembodiments. (Portions of wireless charger device 6600, in particularenclosure 6606 and annular alignment component 6616 are shown tofacilitate understanding of the connection.) Cable assembly 6800 caninclude a cable 6802, which can be of any length desired and can includemultiple wires (or other electrical conductors) that are electricallyinsulated from each other to carry power, ground, and data signals.Cable 6802 has a proximal end 6804 that can be captively coupled towireless charger device 6600. For example, proximal end 6804 of cable6802 can be inserted through opening 6607 in enclosure 6606 and securedusing a crimp 6806. In various embodiments, crimp 6808 can be welded toenclosure 6606 or to DC shield 6614.

Cable 6802 has a distal end 6808 that can be captively coupled to a bootassembly 6810. Boot assembly 6810 can include a boot housing 6812 madeof a plastic such as polycarbonate, polybutylene terephthalate (PBT), orthe like. A crimp 6814 (e.g., made of stainless steel) can secure distalend 6808 of cable 6802 to the interior of boot housing 6812.

A circuit board 6822 can be disposed inside boot housing 6812. Circuitboard 6822 can include power circuitry such as a DC boost circuit andoptionally an inverter. Circuit board 6822 can also include logiccircuitry to control operation of the power circuitry. Similarly to mainlogic board 6632 described above, the power and/or logic circuitry canbe implemented using integrated circuits mounted on the surface(s) oflogic board 6632. Circuit board 6822 can be connected to a connector6824, which can be, e.g., a USB-C plug connector or other standardconnector. Connector 6824 can be removably connected to an externalpower source (not shown) such as a USB-C adapter module that can beplugged into a standard power outlet.

An electromagnetic interference (EMI) shell 6818 can line the interiorof boot housing 6812 around circuit board 6822. EMI shell 6818 can bemade of a copper alloy (e.g., brass) or other conductive material andcan reduce electromagnetic interference that may be caused by operationof circuitry on circuit board 6822. In some embodiments, crimp 6814 canbe laser-welded to EMI shell 6818. Electrical isolation between circuitboard 6822 and EMI shell 6818 can be provided using electricallyinsulating components such as board brace 6820 and clamshells 6826.Faceplate 6828 can be disposed over the distal end of circuit board 6822and secured to boot housing 6812 such that connector 6824 protrudesthrough the opening in faceplate 6828. In some embodiments, the interiorof boot housing 6812 can be filled with a thermally conductive pottingmaterial prior to attaching faceplate 6828 to improve heat transfer awayfrom circuit board 6822.

In some embodiments, all power circuitry can be disposed on circuitboard 6822, and cable 6802 can carry alternating current to wirelesscharger device 6600. In these embodiments, main logic board 6632 withinwireless charger device 6600 can couple the AC wires of cable 6802 tocoil 6620. In other embodiments, circuit board 6822 may include aportion of the power circuitry, e.g., a DC boost circuit, while otherportions of the power circuitry (e.g., an inverter) are disposed on mainlogic board 6632. It will be appreciated that power circuitry cangenerate significant amounts of heat and that placing some or all of thepower circuitry in boot assembly 6810 rather than within enclosure 6606can reduce the amount of heat generated within enclosure 6606. In someembodiments, logic circuitry on main logic board 6632 can monitor thetemperature locally, in boot assembly 6810 (e.g., based on signals fromcircuit board 6822), and in the portable electronic device being charged(e.g., using Qi communication protocols) and can reduce the chargingcurrent if temperature at any monitored location exceeds a preset upperlimit. Providing high thermal conductivity in boot assembly 6810 canavoid having boot assembly 6810 become a limiting factor for chargingperformance.

Regardless of where the power circuitry is located, main logic board6632 within enclosure 6606 can include logic circuits to monitor thebehavior of coil 6620 and to control any power circuitry that may belocated on main logic board 6632 and/or to send control signals tocircuit board 6822 via data wires included in cable 6802 (e.g.,implementing I²C or other point-to-point communication protocols).Circuit board 6822 can include logic circuits to respond to controlsignals received from main logic board 6632, e.g., by controlling powercircuitry located on circuit board 6822.

It will be appreciated that wireless charger device 6600 and associatedcable assembly 6800 are illustrative and that variations andmodifications are possible. For example, the particular configuration ofthe charging coil assembly, the annular magnetic alignment component,and NFC coil assembly can be modified, e.g., according to any of theembodiments described herein. In some embodiments, an NFC coil can beomitted entirely. In some embodiments, all power and logic circuitry canbe located on main logic board 6632, and boot assembly 6810 can bereplaced by a standard cable boot assembly with a plug connector, suchas a USB-C boot assembly. Further, the puck shape is not required, and awireless charger device can have a larger form factor and/or a differentshape. For example, a wireless charger device can be rectangular and canincorporate a rotational alignment component as described in section 2above. A wireless charger device can be designed to meet variousstandards for avoiding demagnetization of magnetic-stripe cards placedon it; for example, the wireless charger device may be HiCo safe (i.e.,does not demagnetize cards that were magnetized to the HiCo standard)but not LoCo safe (i.e., may demagnetize cards that were magnetized tothe LoCo standard).

6.2. Portable Electronic Devices

Examples of portable electronic devices incorporating annular magneticalignment components are described above, e.g., with reference to FIGS.12A-12B, 16, and 50-52. Another example will now be described.

FIG. 69A shows an example of a portable electronic device 6900. In thisexample, portable electronic device 6900 is a smart phone that has awireless charging module 6902 that incorporates an inductive receivercoil assembly, annular alignment magnets, and an NFC reader coil.Wireless charging module 6902 is described further below. A conduit 6904provides a pathway for electrical connections between wireless chargingmodule 6902 and other device components 6906, which can include, e.g., amain logic board for the portable electronic device, power managementcircuitry, battery, and the like. The particular configuration ofcomponents 6906 is not relevant to understanding the present disclosure.Portable electronic device 6900 can also include a rotational alignmentcomponent 6908, which can be implemented according to any of theembodiments described in section 2 above.

FIG. 69B shows a cross section view of wireless charging module 6902through cut line A-A of FIG. 69A. Wireless charging module 6902 caninclude a charging coil assembly 6912, which can include an inductivecharging coil 6913 and shielding components 6914. The particular designof charging coil assembly 6912 is not critical to understanding thepresent disclosure. Wireless charging module 6902 can also include anannular magnetic alignment component 6916, which can be animplementation of any of the secondary annular magnetic alignmentcomponents described above. Wireless charging module 6902 can alsoinclude an NFC coil 6960, which can be disposed in a gap between annularmagnetic alignment component 6916 and charging coil assembly 6912. NFCcoil 6960 can be, e.g., a single-turn two-stranded copper wire disposedon or within a shim 6962, which can be made of polycarbonate or thelike. In some embodiments, shim 6962 can facilitate manufacturing of NFCcoil 6960 and alignment of NFC coil 6960 with other components ofwireless charging module 6902.

FIG. 70 shows a more detailed top view of wireless charging module 6902according to some embodiments. As described in sections 1 and 3 above,annular alignment component 6916 can include a number of arcuate magnets6918 arranged in an annular configuration, and each arcuate magnet 6918can have a magnetic orientation with a radial component. A gap 6940 canbe provided between arcuate magnets 6918 a and 6918 b to facilitateelectrical connections to NFC coil 6960 and to wireless charging module6902. In particular, terminals 6962 a, 6962 b of NFC coil 6960 canextend into gap 6940. Likewise, outer terminal 6912 a of the inductivecoil of charging assembly 6912 can also extend into gap 6940. Innerterminal 6912 b of the inductive charging coil of coil assembly 6912 canbe exposed through a central opening in the coil shield. As shown inFIG. 69A, conduit 6904 can extend to gap 6940 and over the center ofwireless charging module 6902 and can include conductive traces or wiresto provide electrical connections between wireless charging module 6902and other components 6906. In some embodiments, other components 6906can include NFC reader circuit components coupled to NFC coil 6960 and amagnetometer (or other sensor) and associated control logic to triggeroperation of NFC coil 6960 when an accessory having a complementaryannular magnetic alignment component comes into proximity.

NFC coil 6960 can be implemented in various ways, including single-turncoils fabricated using a variety of manufacturing techniques. FIGS.71A-71D show cross section views of NFC coils that can be used inwireless charging module 6902 according to various embodiments. FIG. 71Ashows a double-stranded wire 7102 disposed in a coil shim 7104 (similarto the embodiment of FIG. 69B). FIG. 71B shows a triple-stranded wire7112 disposed in a coil shim 7114. In some embodiments, one strand ofwire 7112 can be a nonconductive (or dummy) strand, which may provideimproved RF performance for the NFC coil. FIG. 71C shows an embodimentin which coil 7122 is insert-molded into a shim 7124. For example, asingle-turn coil 7122 can be stamped from a copper foil, after whichshim 7124 can be molded around coil 7122. Stamping and insert moldingcan allow custom shaping of the NFC coil, e.g., varying width orthickness of the stamped coil along its length, which may provideperformance improvements. FIG. 71D shows an embodiment in which coilstrands 7122 a, 7122 b are needle-dispensed into a shim 7134. A needledispenser can deposit wires 7122 a, 7122 b onto molded plastic shim7134; the wires can be heated during deposition so that they embed intothe softened plastic. As with stamping and insert molding,needle-dispensing can allow custom shaping of the NFC coil, e.g.,varying the strand cross-section and/or separation distance betweenstrands along the length of the coil. Any of these or other techniquesfor forming an NFC coil can be used.

It will be appreciated that portable electronic device 6900 and wirelesscharging module 6902 are illustrative and that variations andmodifications are possible. For example, it is assumed that coilassembly 6912 operates as a receiver coil to receive power via wirelesspower transfer. In some embodiments, coil assembly 6912 can bereconfigurable as a transmitter coil to provide power to another device.Moreover, the particular configuration of the charging coil assembly,the annular magnetic alignment component, and NFC coil assembly can bemodified to suit a specific application, e.g., according to any of theembodiments described herein. In some embodiments, an NFC coil can beomitted entirely.

6.3. Cases

Examples of cases for a portable electronic device are described above,e.g., with reference to FIGS. 27, 55-61, and 63. Another example willnow be described. For purposes of description, it is assumed that thecase is a tray that covers the back and side surfaces of the portableelectronic device, leaving the front surface (which may include adisplay) exposed. It is also assumed that at least the rear panel of thetray is made of a transparent material (e.g., transparent plastic) sothat the back surface of the portable electronic device is visiblethrough the back panel. It should be understood that neither of theseassumptions is required; a case can have a variety of form factors, canbe made of a variety of materials, and may or may not have a transparentportion.

FIG. 72 shows an rear view of a case 7200 according to some embodiments.Case 7200 can be a case for a smart phone (e.g., smart phone 6900 ofFIG. 69) or other portable electronic device. Case 7200 can be shaped asa tray and can have a rear panel 7202 that covers the back surface ofthe portable electronic device when case 7200 is placed on the portableelectronic device. Rear panel 7202 can be made of a rigid material suchas plastic, and the material can be a transparent material. Rear panel7202 need not cover all of the rear surface of the portable electronicdevice; for example, a cutout area 7203 can be provided to expose a rearcamera lens of the portable electronic device. Side panels 7204 of case7200 can be made of a more pliant material with a higher coefficient offriction and can include lips or other surface features that canfacilitate securing a phone into case 7200. The particular constructionof side panels 7204 is not relevant to understanding the presentdisclosure.

Rear panel 7202 can include an annular magnetic alignment assembly 7206and a rotational alignment assembly 7210. Annular magnetic alignmentassembly 7206 can include implementation of any of the auxiliary annularmagnetic alignment components described above, as well as an NFC coiland tag circuit. Rotational alignment assembly 7210 can include animplementation of any of the rotational alignment components describedabove. In some embodiments, case 7200 can be a charge-through accessorythat allows a portable electronic device to receive power from awireless charger device without removing case 7200.

In the absence of transparent magnetic materials, annular magneticalignment assembly 7206 and rotational alignment assembly 7210 areassumed to include opaque elements, and rear panel 7202 would not betransparent in the regions occupied by annular magnetic alignmentassembly 7206 and rotational alignment assembly 7210. In someembodiments, the magnetic alignment components can be designed to reducedisruption of the transparent esthetic of back panel 7202. For example,as shown in FIG. 72, rotational alignment assembly 7210 can be shapedwith rounded corners to echo the round shape of annular alignmentassembly 7206. Annular alignment assembly 7206 can be constructed usingdesign techniques that minimize the radial width of the opaque annulus.In some embodiments, some or all surfaces of annular alignment assembly7206 and rotational alignment assembly 7210 can be covered with anopaque cosmetic material (e.g., a plastic or adhesive that is white orcolored to match the side surfaces 7204 of case 7200. This opaquecosmetic material can conceal the internal structures of annularalignment assembly 7206 and rotational alignment assembly 7210 from viewwhen case 7200 is in use.

In various embodiments, annular alignment assembly 7206 can beimplemented using techniques described in section 5.3 above (e.g., withreference to FIGS. 59-61 and 63). In other embodiments, the design canbe modified to further reduce the radial width of annular alignmentassembly 7206. FIG. 73A shows a simplified axial view of internalcomponents of an annular alignment assembly 7206 according to someembodiments, and FIG. 73B shows a cross section through cut line 7322 ofFIG. 73A.

Annular alignment assembly 7206 can include an annular magneticalignment component 7370, which can be an implementation of any of theauxiliary magnetic alignment components described above. For example,auxiliary magnetic alignment component 7370 can include a number ofarcuate magnets 7372 arranged in an annular configuration. Each arcuatemagnet 7372 can have a quad-pole configuration with an inner arcuateregion having magnetic polarity oriented in a first axial direction, anouter arcuate region having magnetic polarity oriented in a second axialdirection opposite the first direction, and a central non-magnetizedregion between the inner arcuate region and the outer arcuate region. AnNFC tag circuit subassembly 7366 can include an annular NFC antennalcoil 7304 disposed inboard and near the inner edge of annular magneticalignment component 7370 and an NFC tag circuit 7302 disposed in a gapbetween magnets 7372 a, 7372 b. FIG. 73B shows the positioning of NFCantenna coil 7304 relative to annular alignment component 7370. NFCantenna coil 7304 can be a wound wire coil of, e.g., 5 or 6 turns,formed on a tape layer 7306.

FIG. 73C shows a more detailed view of NFC tag circuit 7302 according tosome embodiments. As shown, NFC tag circuit 7302 can include tag circuitcomponents 7332 disposed on a flexible PCB 7334. Like other NFC tagcircuit components referred to herein, tag circuit components 7332 canbe of conventional design and can include a tag chip and supportingcomponents such as capacitors. NFC antenna coil 7304 can terminate intoflexible PCB 7334.

As shown in FIG. 73B, using wound NFC antenna coil 7304 can allow theradial width of NFC antenna coil 7304 to be reduced relative toetched-coil embodiments described in section 5.3 above. To furtherreduce width, arcuate magnets 7372 can be made with a reduced radialwidth. In some embodiments, to compensate for the reduction in magneticfield strength resulting from reduced width, the thickness of arcuatemagnets 7372 can be increased.

FIG. 74 shows an exploded view of annular alignment assembly 7206 androtational alignment assembly 7210 according to some embodiments. Shownat the bottom and top of FIG. 74 are a carrier sheet 7402 and pull tab7404. Carrier sheet 7402 and pull tab 7404 can be made ofsilicone-coated PET or the like. In some embodiments, carrier sheet 7402and pull tab 7404 are used to facilitate construction of annularalignment assembly 7206 and rotational alignment assembly 7210 and areremoved before or during installation of annular alignment assembly 7206and rotational alignment assembly 7210 into an accessory. Annularalignment assembly 7206 can include a bottom film 7410, a coil shim7412, NFC antenna coil 7304, PCB 7334, annular alignment component 7370,and a cosmetic cap 7414. Rotational alignment assembly 7210 can includea bottom film 7420, one or more rotational alignment magnets 7422, and acosmetic cap 7424. Rotational alignment magnet(s) 7422 can implement arotational alignment component as described in section 2 above; variousmagnetization patterns can be used.

Bottom films 7410, 7420 can be made of materials such as an industrialfilm coated with pressure-sensitive adhesive. Coil shim 7412 can provideheight alignment for NFC coil 7304 and PCB 7334 with annular alignmentcomponent 7370. In some embodiments, coil shim 7412 can have a patternedsection 7413 that has openings corresponding to the locations of tagcircuit components 7332 (which are on the underside of PCB 7334 in theview shown in FIG. 74). Patterned section 7413 can help to provideuniform thickness for annular alignment assembly 7206, avoiding bumps ordimples associated with tag circuit components 7332. Terminal ends 7415a, 7415 b of NFC coil 7304 can connect to pads on PCB 7334. PCB 7334 canfit into gap 7417 in annular alignment component 7370. Cosmetic caps7414, 7424 can be made of polycarbonate and adhered to magneticalignment components 7370, 7422 using pressure-sensitive adhesive. Asnoted above, cosmetic caps 7414, 7424 can have a color and/or patternselected for esthetic effect.

FIG. 75 shows a cross-section view of a portion of rear panel 7202 ofcase 7200 according to some embodiments, showing a portion of annularalignment assembly 7206. Rear panel 7202 has an inner surface 7501 thatwould be oriented toward the interior of the case, contacting the backsurface of a portable electronic device that is inserted into the case.Rear panel 7202 also has an outer surface 7503, which is an exteriorsurface that is visible when a portable electronic device is insertedinto the case. In this example, outer surface 7503 has a raised area inthe vicinity of annular alignment assembly 7206; however a raised areais not required, and outer surface 7503 of rear panel 7202 can be flat.Annular alignment assembly 7206 can be inset into outer surface 7503with cosmetic cap 7414 facing outward. Gaps between the sides of annularalignment assembly 7206 and rear panel 7202 can be filled, e.g., by anopaque liquid adhesive 7520.

It will be appreciated that case 7200, annular alignment assembly 7206,and rotational alignment assembly 7210 are illustrative and thatvariations and modifications are possible. For example, an alignmentassembly similar to assembly 7206 can be constructed for any of thecombinations of NFC tag circuits and annular magnetic alignmentcomponents described in section 5 above, and an annular alignmentassembly can be inserted into a rear panel of a case, which might betransparent, translucent, or opaque. A rotational alignment component orassembly can be included or omitted as desired. Further, an annularalignment assembly can be inserted into other types of accessories, notlimited to cases, with or without a rotational alignment assembly.

Annular alignment assembly 7206 is designed for use in a rigid case orother accessory. However, cases and other accessories need not be rigid.For example, a case can be formed as a sleeve having front and rearpanels with an open end (or “throat”) into which a portable electronicdevice can be inserted so that the front and back sides of the portableelectronic device are covered. For ease of insertion and removal, it canbe helpful to construct the front and rear panels with at least somedegree of flexibility. In some embodiments, a flexible annular magneticalignment component can be provided by constructing the annular magneticalignment component from a thin magnet made of polymers infused with apowdered ferromagnetic material or the like. Flexible or rubberizedpolymers can be used so that the resulting magnet has some flexibility.In some embodiments, a single flexible annular magnet can be formed, ora flexible annular magnetic alignment component can be formed ofmultiple arcuate sections. The axial thickness may be kept small tooptimize flexibility. Flexible magnets, however, tend to have lowermagnetic field strength than rare earth magnets. In some embodimentswhere portable electronic device uses a magnetometer to detect proximityof an accessory having an annular alignment component (e.g., asdescribed in section 5.4 above), the magnetometer may not be able toreliably sense the field of the flexible magnet without settingthresholds so low as to result in a high rate of false positives.Accordingly, in some embodiments, a flexible annular alignment componentcan be modified to increase its magnetic field strength. For example,the radial width of the flexible annular alignment component can beincreased, either around the entire circumference or just in a region(e.g., a quadrant) close to the magnetometer. The latter option maycreate a rotational asymmetry of magnetic field that can result in a“clocking” effect. As another technique to increase sensed magneticfield, an additional flexible magnet (referred to herein as a“triggering” magnet) can be placed outboard of the annular alignmentcomponent. For example, a small square or rectangular triggering magnetcan be placed at a location that would be close to the magnetometer(e.g., magnetometer 5080 in FIG. 50) when the sleeve is in alignmentwith the mobile device. In some embodiments, the sleeve may be acharge-through accessory, and it may be desirable to avoid having thetriggering magnet interfere with detection of a second accessoryattaching to the distal surface of the charge-through accessory.Accordingly, a triggering magnet can have a weak magnetic field that canbe sensed due to short distance to the magnetometer.

7. Alignment Modules

As described above, magnetic alignment components can be incorporatedinto a variety of devices, including portable electronic devices andaccessories such as cases and wireless charger devices. In someembodiments, a magnetic alignment component can be provided in analignment module (optionally with other components such as an inductivecharging coil) that can be incorporated into a device. An alignmentmodule can include an annular alignment component (which can be aprimary, secondary, or auxiliary alignment component) enclosed in apackage that is sized and shaped to facilitate incorporation into avariety of devices in which an alignment component can be included. Insome embodiments, the alignment module can also include a rotationalalignment component (as described in section 2 above) enclosed in thesame package and held in the desired position relative to the annularalignment component. In some embodiments, the package may also enclose awireless charging coil and/or an NFC tag circuit as described above. Inembodiments where the alignment module includes active circuitry (suchas an inductive charging coil assembly and/or logic board), electricalcontacts may be provided at the exterior of the package to enableconnection to the included active circuitry. Examples will now bedescribed.

7.1. Charger Alignment Modules

Alignment modules according to some embodiments may include a wirelesscharging coil and an annular alignment component. FIGS. 76A and 76B showtop and bottom perspective views of a charger alignment module 7600according to some embodiments. Charger alignment module 7600 has atwo-piece housing that includes a cap 7601 (best seen in FIG. 76A) and arear enclosure 7606 (best seen in FIG. 76B). Cap 7601 can provide acosmetic face that may be visible to a user when charger alignmentmodule 7600 is incorporated into an accessory device such as a dockingstation. Cap 7601 can include a charging surface 7604 and a surroundingrim region 7602. Charging surface 7604 can be made of silicone orplastic with a hard-touch coating, or any other material that ispermeable to AC and DC magnetic fields. Rim region 7602 can be made ofplastic or other material that is permeable to DC magnetic fields. Rearenclosure 7606 can be made of metal (e.g., aluminum) and shaped toaccommodate an inductive charging coil and a logic board as describedbelow. In some embodiments, it is assumed that rear enclosure 7606 willnot be visible to a user when charger alignment module 7600 isincorporated into an accessory device such as a docking station. Rearenclosure 7606 can include an opening 7608 with exposed electricalcontacts 7610. As described below, exposed electrical contacts 7610 canbe disposed on a logic board and coupled by conductive traces tocomponents housed inside charger alignment module 7600. In someembodiments, exposed electrical contacts 7610 include contacts forelectrical power for the charging coil and contacts for USB data signals(D+ and D−), power, and ground; however, any combination of contacts maybe provided. In addition, coil calibration contacts 7612 may also beexposed within rear enclosure 7606. In some embodiments, coilcalibration contacts 7612 are exposed during manufacture of chargeralignment module 7600 to support calibration of the inductive chargingcoil inside charger alignment module 7600 (e.g., testing of coilresistance); after calibration, contacts 7612 can be covered with anencapsulating sealant material prior to delivering charger alignmentmodule 7600 to a third party for incorporation into an accessory device.

FIG. 77 shows an exploded view of charger alignment module 7600according to some embodiments. Cap 7601 is shown at the top, and rearenclosure 7606 is shown at the bottom. A primary annular alignmentcomponent 7716 is disposed under cap 7601, e.g. under rim region 7602.Primary annular alignment component 7716 can be an implementation of anyof the primary annular alignment components described above. Forexample, primary annular alignment component 7716 can include primaryarcuate magnets 7717 arranged in an annular configuration with eachprimary arcuate magnet 7717 having a quad-pole configuration with aninner arcuate magnetic region having magnetic polarity oriented in afirst axial direction, an outer arcuate magnetic region having magneticpolarity oriented in a second axial direction opposite the firstdirection, and a central non-magnetized region between the inner arcuatemagnetic region and the outer arcuate magnetic region. An annular DCmagnetic shield 7719 can be disposed on the distal surface of primaryarcuate magnets 7717. As described above, DC magnetic shield 7719 can bemade of steel or other material having high magnetic permeability andcan redirect magnetic fields to prevent them from propagating beyond thedistal side of primary annular alignment component 7716.

An inductive charging coil assembly 7712 can be disposed inboard ofprimary annular alignment component 7716. Inductive charging coilassembly 7712 can include an inductive charging coil 7720, an electricshield 7722 disposed on a proximal side of inductive charging coil 7720,an electromagnetic shield 7726 disposed on a distal side of inductivecharging coil 7720, and a shim 7724. Inductive charging coil 7720 can bea wound wire coil. Electric shield 7722 can include a thin layer ofconductive material to block or reduce AC electric fields duringoperation of coil 7720 while being permeable to magnetic flux.Electromagnetic shield 7726 can be a ferrite or the like that extendsover the distal surface and outer sides of coil 7720. Shim 7724 can bemade of plastic or other nonconductive material and can be provided tolevel coil 7720 with the top of electromagnetic shield 7726, providingadditional support for charging surface 7604. A variety of inductivecharging coil assemblies can be used as inductive charging coil assembly7712.

A fence 7728 can be formed of aluminum or the like and interposedbetween the outer side of electromagnetic shield 7726 and the inner sideof DC shield 7719. Fence 7728 can provide isolation of electromagneticshield 7726 from DC shield 7719, helping to keep DC magnetic flux fromentering the region of coil 7720, which may improve charging efficiency.

DC shield 7718, fence 7728, and electromagnetic shield 7726 can bemounted on a midplate 7730. Midplate 7730 can be made of aluminum orother electrically conductive material. An opening 7731 through midplate7730 can be provided to allow electrical connections to the endterminals of coil 7720. In some embodiments, midplate 7730 can be weldedto rear enclosure 7606 and to fence 7728. In some embodiments, thethickness of annular alignment component 7716 can be equal to thethickness of coil assembly 7712. In embodiments where annular alignmentcomponent 7716 is thinner than coil assembly 7712, spacers (similar tospacers 6615 of FIG. 67) can be used to position magnets 6626 adjacentto cap 6602.

A logic board 7732 can be mounted on the distal surface of midplate 7730using an adhesive 7734, which can be, e.g., a temperature sensitiveadhesive. Logic board 7732 can be a printed circuit board withelectronic components mounted on the underside (not shown in FIG. 77).The electronic components can include power circuitry (e.g., boostcircuit, inverter) to drive inductive charging coil 7720 and controlcircuitry (e.g., a microcontroller, FPGA, ASIC, or the like) to controloperation of the power circuitry. Examples of suitable components andcircuits are known in the art, and a detailed description is omitted.Rear enclosure 7606 can be shaped to accommodate the electroniccomponents on the underside of logic board 7732, and midplate 7730 canprovide shielding between logic board 7732 and coil 7720. The undersideof logic board 7732 can also include external electrical contacts thatalign with opening 7608 in rear enclosure 7606 (e.g., contacts 7610,7612 as shown in FIG. 76B). The top surface of logic board 7732 (shownin FIG. 77) can be partially covered by adhesive 7734, leaving certainregions exposed. For example, exposed region 7735 can align with opening7731 in midplate 7730 and may include contacts 7736 for connecting tothe terminals of coil 7720. As another example, a grounded region 7738can be exposed at the periphery of logic board 7732. Grounded region7738 can provide electrical grounding for midplate 7730.

It will be appreciated that charger module 7600 is illustrative and thatvariations and modifications are possible. A variety of inductive coilsand shielding arrangements can be used, and any of the annular alignmentcomponents described above may also be included. Further, while chargermodule 7600 is not shown as including an NFC tag circuit and coil, thoseskilled in the art with access to the present disclosure will appreciatethat an NFC tag circuit and coil can be incorporated similarly to otherexamples of wireless charger devices described above. In someembodiments, charger module 7600 can include a wound NFC coil terminatesto external electrical contacts 7608, and a third-party accessorymanufacturer can couple the NFC coil to an external NFC tag circuit,allowing the accessory manufacturer to control the tag data. Exposedcontacts are helpful to enable a third party to connect external wiringor other components to charger module 7600. In the embodiment shown, theexternal contacts are exposed through the rear surface of the housing;however external contacts can be exposed through any surface of thehousing. For cosmetic reasons, it may be undesirable to expose theexternal contacts through the front surface of the charger module and toinstead use surfaces (such as the rear surface or a side surface) thatare expected to be hidden from view when the charger module isincorporated into an accessory.

In addition, a puck shape is not required, and a charger module can havea larger form factor. For example, a charger module can have arectangular or teardrop-shaped top surface and can incorporate arotational alignment component as described in section 2 above. FIG. 78shows a top perspective view of a teardrop-shaped charger module 7800according to some embodiments. Charger module 7800 can be similar oridentical to charger module 7600 except for the shape of the housing7801. Top cap 7802 can include a charging area 7804 under which anassembly including a charging coil assembly, annular magnetic alignmentcomponent (e.g., as shown in FIG. 77), and control circuitry can beprovided. Top cap 7802 can also include an extension portion 7810, and arotational magnetic alignment component 7812 can be disposed inextension portion 7810 at an appropriate distance from the center of theannular magnetic alignment component as described above in section 2.The bottom enclosure of charger module 7800 can also extend similarly totop cap 7802. Other shapes, including rectangular shapes (e.g., as shownin FIG. 16), can also be provided.

7.2. Accessory Insert Modules

In some embodiments, an alignment module is provided for insertion intoa “passive” accessory that does not include an inductive chargingcircuit. FIG. 79A is a front view and FIG. 79B is a top view of anaccessory insert module 7900 according to some embodiments. As shown inFIG. 79A, accessory insert module 7900 can be shaped as a rectangle withrounded corners as shown (or with square corners if desired) and canhave flat front and back surfaces. As shown in FIG. 79B, accessoryinsert module 7900 can have a layered structure with front and backouter layers 7902, 7904, which can be made of encapsulant material(e.g., plastic) and a central magnet-holding layer 7910. Adhesive layers7906, 7908 can be disposed between front and back outer layers 7902,7904 and central magnet-holding layer 7910.

FIG. 80 shows an exploded view of accessory insert module 7900 accordingto some embodiments. Central magnet-holding layer 7910 can be made ofplastic with an annular opening 8026 and a rectangular opening 8032.Annular opening 8026 can be sized and shaped such that an annularalignment component 8070 fits within annular opening 8026. Annularalignment component 8070 can be an implementation of any of theauxiliary annular alignment components described above. For example,auxiliary annular alignment component 8070 can include primary arcuatemagnets 8072 arranged in an annular configuration with each primaryarcuate magnet 8072 having a quad-pole configuration with an innerarcuate magnetic region having magnetic polarity oriented in a firstaxial direction, an outer arcuate magnetic region having magneticpolarity oriented in a second axial direction opposite the firstdirection, and a central non-magnetized region between the inner arcuatemagnetic region and the outer arcuate magnetic region. Rectangularopening 8032 can be sized and shaped such that a rotational alignmentcomponent 8022 fits within rectangular opening 8032. Rotationalalignment component 8022 can be an implementation of a rotationalalignment component as described above and can include, for example, oneor more magnets having a z-pole, quad-pole, triple-pole, or annulusdesign configuration.

In some embodiments, magnet-holding layer 7910, annular alignmentcomponent 8070, and rotational alignment component 8022 can all have thesame z-height, which can help to keep accessory insert module 7900 flatin the lateral (xy) plane, particularly where the overall z-height ofaccessory insert module 7900 is small. In the example shown,magnet-holding layer 7910 includes a region 8030 inboard of annularalignment component 8070 that is detached from the rest ofmagnet-holding layer 7910. As shown, region 8030 can be occupied by adiscrete disc of material having the same thickness as the rest ofmagnet-holding layer 7910, and this too can help to preserve the lateralflatness of accessory insert module 7910. In other embodiments, region8030 can be empty.

Accessory insert module 7900 can be used in an accessory such as a casefor a portable electronic device. To reduce bulk of the case, it may bedesirable for accessory insert module 7900 to be quite thin, e.g., atotal thickness of about 1 mm. For example, front and back outer layers7902 and 7904 and magnet-holding layer 7910 can be made of apolycarbonate film such as LEXAN™ SD8B24 film (a product of SABICInnovative Plastics). Front and back outer layers 7902 and 7904 can eachhave a thickness of about 0.2 mm while magnet-holding layer 7910 canhave a thickness of about 0.5 mm. (As noted above, the thickness ofannular alignment component 8070 and rotational alignment component 8072can be the same as the thickness of magnet-holding layer 7910.) Adhesivelayers 7906 and 7908 can be, e.g., pressure sensitive adhesive with athickness of about 0.2 mm. It should be understood that these dimensionscan be modified as desired. In general, thinner front and back outerlayers allow a given annular alignment component 8070 and rotationalalignment component 8072 to exert stronger magnetic forces oncomplementary devices, and thinner magnets (and magnet-holding layer7910) allow the overall thickness of an accessory incorporating insertmodule 7900 to be reduced.

In some embodiments, accessory insert module 7900 can be made of opaquematerials and can be inserted into a variety of accessories such asprotective cases, sleeves, trays, and the like. The opacity of accessoryinsert module 7900 may interfere with certain esthetic options, such asa transparent case back. Some embodiments of accessory insert modulescan provide a reduced region of opacity as compared to accessory insertmodule 7900. FIG. 81 shows an exploded view of an accessory insertmodule 8100 according to some embodiments. Accessory insert module 8100has an annular shape, with an annular front enclosure 8102 and anannular rear enclosure 8104 surrounding annular alignment component 8170Annular alignment component 8170 can be an implementation of any of theauxiliary annular alignment components described above. For example,auxiliary annular alignment component 8170 can include primary arcuatemagnets 8172 arranged in an annular configuration with each primaryarcuate magnet 8172 having a quad-pole configuration with an innerarcuate magnetic region having magnetic polarity oriented in a firstaxial direction, an outer arcuate magnetic region having magneticpolarity oriented in a second axial direction opposite the firstdirection, and a central non-magnetized region between the inner arcuatemagnetic region and the outer arcuate magnetic region. Adhesive layers8106, 8108, each of which can be, e.g., a pressure-sensitive adhesive,can hold annular alignment component in place within an enclosure formedby front enclosure 8102 and rear enclosure 8104. Front enclosure 8102and rear enclosure 8104 can be made, e.g., of injection moldedpolycarbonate or other similar material. Accessory insert module 8100can be opaque, but because of its reduced opaque area relative toaccessory insert module 7900, accessory insert module 8100 may be moreesthetically appealing in transparent cases and other applications wherea transparent surface is desired.

In the embodiment shown in FIG. 81, front enclosure 8102 and/or rearenclosure 8104 can have sidewalls so that magnets 8172 are surrounded onall sides. The joint where front enclosure 8102 and rear enclosure 8104meet can be formed in several ways. FIGS. 82 and 83 show partialcross-section views of accessory insert modules according to variousembodiments, illustrating options for joining front enclosure 8102 andrear enclosure 8104. In FIG. 82, front enclosure 8102 and rear enclosure8104 of accessory insert module 8100 can be joined by an ultrasonic orlaser weld 8210, fully enclosing annular alignment component 8170. FIG.83 shows a variation in which a front enclosure 8102′ of accessoryinsert module 8100 includes a notch 8310 while rear enclosure 8104′includes a projection 8312 that fits into notch 8310. For example, frontenclosure 8102′ with notch 8310 can be formed in a first injectionmolding process, after which magnets are arranged in front enclosure8102′ to form annular alignment component 8170. Thereafter, a secondinjection molding process can be used to form rear enclosure 8104′,filling in notch 8310.

In still other embodiments, sidewalls can be formed separately fromfront enclosure 8102 and rear enclosure 8104, providing a “stacked”construction similar to accessory insert module 7900 described above.FIG. 84 is a partial cross section view of an annular accessory insertmodule 8100″ according to some embodiments with a “stacked”construction. Annular accessory insert module 8100″ can have the sameannular shape as accessory insert module 8100. In this embodiment,however, front enclosure 8102″ and rear enclosure 8104″ can be planarannular structures formed of polycarbonate or the like. Sidewalls 8410 aand 8410 b can be formed as concentric annular rings of polycarbonatehaving a thickness that can be the same as (or slightly greater than)the thickness of annular alignment component 8170. Adhesive layers 8406,8408, which can be, e.g., pressure-sensitive adhesive, can hold thestructure together.

It will be appreciated that these accessory insert modules areillustrative and that variations and modifications are possible. Avariety of materials can be used, and any of the annular alignmentcomponents described above may be included. Further, while the variousaccessory insert modules are not shown as including an NFC tag circuitand coil, those skilled in the art with access to the present disclosurewill appreciate that an NFC tag circuit and coil can be incorporatedsimilarly to examples of accessory devices described above.

8. Additional Embodiments

While the invention has been described with reference to specificembodiments, those skilled in the art will appreciate that variationsand modifications are possible. For instance, although the annularalignment modules are described as being made from arcuate magnets thatform sectors, it will be understood that if the magnets are sufficientlysmall relative to the dimensions of the annular structure, trapezoidalor square magnets can approximate the behavior of arcuate magnets.Magnetic alignment components can have any dimensions, and annularmagnetic alignment components can be used with or without rotationalalignment components and with or without NFC circuitry. Where NFCcircuitry is present, a given device can have NFC reader circuitry orNFC tag circuitry (or both) in combination with any of a primary,secondary, or auxiliary annular magnetic alignment component, and avariety of NFC coil geometries can be implemented. Magnetic alignmentcomponents can be used with an inductive charging coil to facilitatealignment of the coils as described above, or a magnetic alignmentcomponent can be present in a device that does not have an inductivecharging coil. Further, a portable electronic device that has a magneticalignment component around an inductive charging coil can be charged bya wireless charger device that does not have a magnetic alignmentcomponent, and conversely, a wireless charger device that has a magneticalignment component can be used to charge a portable electronic devicethat has an inductive charging coil but not a magnetic alignmentcomponent. In these situations, the magnetic alignment component may notfacilitate alignment between the devices, but it need not interfere withwireless power transfer.

In addition, while a portable electronic device has been described asreceiving power wirelessly, those skilled in the art will appreciatethat an inductive power coil may be operable to transmit as well asreceive power wirelessly, and in some embodiments a portable electronicdevice can be reconfigurable to operate either as a transmitter orreceiver for wireless power transfer.

Further, while it is contemplated that magnetic alignment components ofthe kind described herein can be used to facilitate alignment betweentransmitter and receiver coils for wireless power transfer betweendevices, use of magnetic alignment components is not so limited, andmagnetic alignment components can be used in a variety of contexts tohold one device in relative alignment with another, regardless ofwhether either or both devices have wireless charging coils. Thus, forinstance, a tripod (or other type of stand), which can hold a portableelectronic device in a particular positon and orientation, can include aprimary annular magnetic alignment component (and a rotational alignmentcomponent) to hold the portable electronic device in place; the magneticalignment component can be used in addition to or instead of mechanicalretention features to secure the portable electronic device to thetripod.

Accordingly, ecosystems of devices are contemplated. The ecosystem caninclude a variety of portable electronic devices having various formfactors, such as smart phones, tablets, or other devices that canoperate on battery power and can receive power via wireless powertransfer. The ecosystem can also include a variety of wireless chargerdevices such as pucks, mats, docks, or the like. The ecosystem can alsoinclude “charge-through” accessories (such as cases) that may beinterposed between a portable electronic device and a wireless chargerdevice; the charge-through accessory is designed to permit magnetic fluxto pass through the interposed portion of the accessory to allowwireless charging while the accessory is present. In such an ecosystem,each portable electronic device can be manufactured to include asecondary annular magnetic alignment component (e.g., having a radial ortransverse magnetic orientation as described above) having dimensions ofradial width and outer diameter that are constant across the ecosystem.Each wireless charger device can be manufactured to include a primaryannular magnetic alignment component complementary to the secondaryannular magnetic alignment components of the portable electronic devices(e.g., having a quad-pole configuration as described above), allowingwireless charger devices to be used interchangeably with differentportable electronic devices. Each charge-through accessory can bemanufactured to include an auxiliary annular magnetic alignmentcomponent complementary to the primary and secondary annular magneticalignment components, again allowing interchangeable use of wirelesscharger devices with different charge-through accessories (and portableelectronic devices).

Such ecosystems can also include other passive accessory devices (i.e.,accessory devices that do not include inductive charging coils) that maybe designed to attach to a portable electronic device using magneticalignment components but that do not support charge-through operation.Examples include tripods or other stands, attachable accessory casesthat may hold credit cards or other magnetized items that may besusceptible to demagnetization during wireless power transfer, or otheraccessories that are intended for use with a portable electronic devicethat is not being charged. Such accessory devices can be manufactured toinclude either a secondary annular magnetic alignment component or anauxiliary annular magnetic alignment component and may or may notinclude a rotational alignment component.

Such ecosystems can also include a “retrofitting” accessory device thatmay be used to provide magnetic alignment capability for a portableelectronic device that was originally manufactured without a magneticalignment component. A retrofitting accessory can have one or moremechanical retention features (e.g., sides and lips of a case shaped asa tray) that hold the smart phone (or other portable electronic device)in a fixed relative alignment with the housing of the accessory. Theaccessory can include a secondary magnetic alignment component (matchingthe specifications of the secondary alignment component for theecosystem), and the secondary magnetic alignment component can bepositioned in the retrofitting accessory so that when the portableelectronic device is held in place by the mechanical retentionfeature(s), the inductive charging coil is centered within the secondarymagnetic alignment component. Such an accessory can allow a portableelectronic device that was manufactured without a magnetic alignmentcomponent to enjoy the benefits of magnetic alignment when used withdevices in the magnetic alignment ecosystem.

It should be understood that, within a given ecosystem, any or all ofthe devices that include annular alignment components may also includerotational alignment components as described above. For instance, withinan ecosystem, all portable electronic devices having a secondary annularalignment component that are large enough to accommodate a rotationalalignment component outboard of the secondary annular alignmentcomponent can have a rotational alignment component. Devices having aprimary alignment component or auxiliary alignment component might ormight not have a rotational alignment component, depending on formfactor and intended use.

It should also be understood that, within a given ecosystem, any or allof the devices that include annular alignment components may alsoinclude NFC circuitry for device identification as described above. Forinstance, within an ecosystem, any portable electronic device can havean NFC reader circuit as described above, while any device having aprimary annular alignment component or auxiliary annular alignmentcomponent can have an NFC tag circuit as described above.

It should also be understood that some devices may include multipleannular alignment components. For instance, a wireless charger devicemay be designed with two or more separate wireless charging coils spacedapart from each other to allow multiple portable electronic devices tobe charged at the same time. Each wireless charging coil can have asurrounding primary annular alignment component, and each primaryalignment component can have an associated rotational alignmentcomponent and/or NFC coil.

In some embodiments, an alignment module that includes an annularalignment component can be packaged for easy installation into anaccessory device, wireless charger device, or portable electronicdevice. For example, an alignment module can include a primary,secondary, or auxiliary annular magnetic alignment component asdescribed above in an enclosing structure (or housing) that protects themagnets and holds them in position In some embodiments, a rotationalmagnetic alignment component can be included along with the annularmagnetic alignment component, and in some embodiments, an NFC circuitcan be included. The enclosing structure can be, for instance, a plasticstructure, at least part of which can be transparent. As anotherexample, the alignment module can include a wireless charging coil(e.g., a transmitter coil) centered within the annular alignmentcomponent. The enclosing structure can provide exposed electricalcontacts for making electrical connections to the wireless chargingcoil. Such alignment modules can be made by one entity and sold to adifferent entity to incorporate into devices such as cases, wirelesscharging docks, or the like.

Various features described herein related to detection of devices andexchange of information (e.g., using NFC) can be realized using anycombination of dedicated components and/or programmable processorsand/or other programmable devices. The various processes describedherein can be implemented on the same processor or different processorsin any combination. Where components are described as being configuredto perform certain operations, such configuration can be accomplished,e.g., by designing electronic circuits to perform the operation, byprogramming programmable electronic circuits (such as microprocessors)to perform the operation, or any combination thereof. Further, while theembodiments described above may make reference to specific hardware andsoftware components, those skilled in the art will appreciate thatdifferent combinations of hardware and/or software components may alsobe used and that particular operations described as being implemented inhardware might also be implemented in software or vice versa. Computerprograms incorporating various features described herein may be encodedand stored on various computer readable storage media; suitable mediainclude magnetic disk or tape, optical storage media such as compactdisk (CD) or DVD (digital versatile disk), flash memory, and othernon-transitory media. Computer readable media encoded with the programcode may be packaged with a compatible electronic device, or the programcode may be provided separately from electronic devices (e.g., viaInternet download or as a separately packaged computer-readable storagemedium). Further, in regard to any collection or exchange of informationor data by or between devices, it is well understood that the use ofpersonally identifiable information should follow privacy policies andpractices that are generally recognized as meeting or exceeding industryor governmental requirements for maintaining the privacy of users. Inparticular, personally identifiable information data should be managedand handled so as to minimize risks of unintentional or unauthorizedaccess or use, and the nature of authorized use should be clearlyindicated to users.

Embodiments of the invention can include, but are not limited to, any ofthe following.

In some embodiments, an electronic device (e.g., a portable electronicdevice) can comprise: a housing having an interface surface; aninductive coil disposed within the housing and having an axis normal tothe interface surface, the inductive coil being configured to transferpower wirelessly through the interface surface; and an annular magneticalignment component disposed within the housing coaxial with andoutboard of the inductive coil. The annular magnetic alignment componentcan have a magnetic orientation in a radial direction. The annularmagnetic alignment component can comprise a plurality of arcuatemagnets, and each of the arcuate magnets can have a magnetic polaritythat is oriented in a radially inward (or radially outward) direction.The annular magnetic alignment component can include a gap, and anelectrically conductive path connected to the inductive coil can passthrough the gap. The annular magnetic alignment component can include afirst gap and a second gap on opposite sides of the annular magneticalignment component. A battery can be disposed within the housing, andthe inductive coil can be coupled to the battery. The inductive coil canbe configured to receive and/or transmit power wirelessly through theinterface surface.

In some embodiments, an electronic device (e.g., a wireless chargerdevice) can comprise: a housing having a charging surface; an inductivecoil disposed within the housing and having an axis normal to thecharging surface, the inductive coil being configured to transfer powerwirelessly through the charging surface; and an annular magneticalignment component disposed within the housing coaxial with andoutboard of the inductive coil. The annular magnetic alignment componentcan comprise: an inner arcuate region having a magnetic polarityoriented in a first axial direction; an outer arcuate region having amagnetic polarity oriented in a second axial direction opposite thefirst axial direction; and a non-magnetized central arcuate regiondisposed between the inner arcuate region and the outer arcuate region.The annular magnetic alignment component can comprise a plurality ofarcuate magnets, and each arcuate magnet can have a first region with amagnetic polarity oriented in the first axial direction, a second regionwith a magnetic polarity oriented in the second axial direction, and anon-magnetized region between the first region and the second region.The annular magnetic alignment component can include a gap, and anelectrically conductive path connected to the inductive coil can passthrough the gap. The inductive coil can be configured to transmit and/orreceive power wirelessly through the charging surface.

In some embodiments, an accessory for use with a portable electronicdevice can comprise: a housing having a first interface surface and asecond interface surface opposite the first interface surface; anannular magnetic alignment component disposed within the housing andhaving an axis normal to the first interface surface and the secondinterface surface. The annular magnetic alignment component cancomprise: an inner arcuate region having a magnetic polarity oriented ina first axial direction; an outer arcuate region having a magneticpolarity oriented in a second axial direction opposite the first axialdirection; and a non-magnetized central arcuate region disposed betweenthe inner arcuate region and the outer arcuate region. The annularmagnetic alignment component can comprise a plurality of arcuatemagnets. Each arcuate magnet can have a first region with a magneticpolarity oriented in the first axial direction, a second region with amagnetic polarity oriented in the second axial direction, and anon-magnetized region between the first region and the second region.The annular magnetic alignment component can include a gap. The annularmagnetic alignment component can include a first gap and a second gap onopposite sides of the annular magnetic alignment component.

In some embodiments, a magnetic alignment system can comprise: a primaryalignment component formed of a plurality of primary arcuate magnetsarranged in an annular configuration defining an axis and a secondaryalignment component formed of a plurality of secondary arcuate magnetsarranged in an annular configuration. Each primary arcuate magnet cancomprise: a primary inner arcuate magnetic region having a magneticorientation in a first direction along the axis; a primary outer arcuatemagnetic region having a magnetic orientation in a second directionopposite the first direction; and a non-magnetized primary centralarcuate region disposed between the primary inner arcuate region and theprimary outer arcuate region. Each secondary arcuate magnet having amagnetic orientation that is in a radial direction with respect to acenter of the secondary alignment component. The primary alignmentcomponent can be disposed in a first electronic device surrounding afirst inductive charging coil, and the secondary alignment component canbe disposed in a second electronic device surrounding a second inductivecharging coil; when the primary alignment component and the secondaryalignment component are aligned along a common axis, the first inductivecharging coil and the second inductive charging coil can be also alignedalong the common axis.

In some embodiments, an electronic device (e.g., a portable electronicdevice) can comprise: a housing having an interface surface; aninductive coil disposed within the housing and having an axis normal tothe interface surface, the inductive coil being configured to transferpower wirelessly through the interface surface; an annular magneticalignment component disposed within the housing coaxial with andoutboard of the inductive coil, the annular magnetic alignment componenthaving a magnetic orientation in a radial direction; and a rotationalalignment component comprising a magnet disposed outside an outerperimeter of the annular magnetic alignment component. The rotationalalignment component can comprises a magnet having at least two differentregions of opposing magnetic orientations. In these and otherembodiments, the magnet can have a rectangular shape in a planetransverse to an axis defined by the annular magnetic alignmentcomponent. For example, the at least two different regions of opposingmagnetic orientations can include: a first region extending along afirst long side of the rectangular shape and having a first magneticorientation; and a second region extending along a second long side ofthe rectangular shape and having a second magnetic orientation oppositethe first magnetic orientation. As another example, the at least twodifferent regions of opposing magnetic orientations can include: a firstregion extending along a first long side of the rectangular shape andhaving a first magnetic orientation; a second region extending along asecond long side of the rectangular shape and having the first magneticorientation; and a third region extending along the rectangular shapeand positioned midway between the first region and the second region,the third region having a second magnetic orientation opposite the firstmagnetic orientation. In these and other embodiments, the annularmagnetic alignment component can comprise a plurality of arcuatemagnets, each having a magnetic polarity that is oriented in a radiallyinward direction. In these and other embodiments, a battery can bedisposed within the housing, and the inductive coil can be coupled tothe battery. In these and other embodiments, the inductive coil can beconfigured to receive and/or transmit power wirelessly through theinterface surface.

In some embodiments, an electronic device (e.g., a wireless chargerdevice) can comprise: a housing having a charging surface; an inductivecoil disposed within the housing and having an axis normal to thecharging surface, the inductive coil being configured to transfer powerwirelessly through the charging surface; an annular magnetic alignmentcomponent disposed within the housing coaxial with and outboard of theinductive coil; and a rotational alignment component comprising a magnetdisposed outside a perimeter of the annular magnetic alignmentcomponent. In these and other embodiments, the annular magneticalignment component can comprise: an inner arcuate region having amagnetic polarity oriented in a first axial direction; an outer arcuateregion having a magnetic polarity oriented in a second axial directionopposite the first axial direction; and a non-magnetized central arcuateregion disposed between the inner arcuate region and the outer arcuateregion. In these and other embodiments, the rotational alignmentcomponent can comprise a magnet having at least two different regions ofopposing magnetic orientations. For example, the magnet can have arectangular shape in a plane transverse to an axis defined by theannular magnetic alignment component, and the at least two differentregions of opposing magnetic orientations can include: a first regionextending along a first long side of the rectangular shape and having afirst magnetic orientation; and a second region extending along a secondlong side of the rectangular shape and having a second magneticorientation opposite the first magnetic orientation. As another example,the magnet can have a rectangular shape in a plane transverse to an axisdefined by the annular magnetic alignment component, and the at leasttwo different regions of opposing magnetic orientations can include: afirst region extending along a first long side of the rectangular shapeand having a first magnetic orientation; a second region extending alonga second long side of the rectangular shape and having the firstmagnetic orientation; and a third region extending along the rectangularshape and positioned midway between the first region and the secondregion, the third region having a second magnetic orientation oppositethe first magnetic orientation. In these and other embodiments, theannular magnetic alignment component can comprise a plurality of arcuatemagnets. Each arcuate magnet can have a first region with a magneticpolarity oriented in the first axial direction, a second region with amagnetic polarity oriented in the second axial direction, and anon-magnetized region between the first region and the second region. Inthese and other embodiments, the inductive coil can be configured totransmit power wirelessly through the charging surface.

In some embodiments, an accessory for use with a portable electronicdevice can comprise: a housing having a first interface surface and asecond interface surface opposite the first interface surface; anannular magnetic alignment component disposed within the housing andhaving an axis normal to the first interface surface and the secondinterface surface; and a rotational alignment component comprising amagnet disposed outside a perimeter of the annular magnetic alignmentcomponent. In these and other embodiments, the annular magneticalignment component can comprise: an inner arcuate region having amagnetic polarity oriented in a first axial direction; an outer arcuateregion having a magnetic polarity oriented in a second axial directionopposite the first axial direction; and a non-magnetized central arcuateregion disposed between the inner arcuate region and the outer arcuateregion. In these and other embodiments, the rotational alignmentcomponent comprises a magnet having at least two different regions ofopposing magnetic orientations. For example, the magnet can have arectangular shape in a plane transverse to an axis defined by theannular magnetic alignment component, and the at least two differentregions of opposing magnetic orientations can include: a first regionextending along a first long side of the rectangular shape and having afirst magnetic orientation; and a second region extending along a secondlong side of the rectangular shape and having a second magneticorientation opposite the first magnetic orientation. As another example,the magnet can have a rectangular shape in a plane transverse to an axisdefined by the annular magnetic alignment component, and the at leasttwo different regions of opposing magnetic orientations can include: afirst region extending along a first long side of the rectangular shapeand having a first magnetic orientation; a second region extending alonga second long side of the rectangular shape and having the firstmagnetic orientation; and a third region extending along the rectangularshape and positioned midway between the first region and the secondregion, the third region having a second magnetic orientation oppositethe first magnetic orientation. In these and other embodiments, theannular magnetic alignment component can comprise a plurality of arcuatemagnets. Each arcuate magnet can have a first region with a magneticpolarity oriented in the first axial direction, a second region with amagnetic polarity oriented in the second axial direction, and anon-magnetized region between the first region and the second region.

In some embodiments, a portable electronic device (or other electronicdevice) can comprise: a housing having an interface surface; aninductive coil disposed within the housing and having an axis normal tothe interface surface, the inductive coil being configured to transferpower wirelessly through the interface surface; an annular magneticalignment component disposed within the housing coaxial with andoutboard of the inductive coil, the annular magnetic alignment componentincluding a plurality of sectors, each sector having a magneticorientation with a radial component; and a near-field communication(NFC) coil disposed within the housing and coaxial with the inductivecoil, the NFC coil configured to wirelessly exchange signals withanother device through the interface surface. In these and otherembodiments, the NFC coil can be coupled to an NFC reader circuit. Inthese and other embodiments, the NFC coil is positioned in a gap (whichcan be an annular gap) between the inductive coil and the annularmagnetic alignment component. In these and other embodiments, eachsector of the annular magnetic alignment component can comprise one ormore arcuate magnets, each arcuate magnet having a magnetic polarityoriented in a radial direction. In these and other embodiments,alternating sectors of the annular magnetic alignment component can haveopposite magnetic orientations. In these and other embodiments, theannular magnetic alignment component can include a gap between two ofthe sectors. An electrically conductive path connecting the NFC coil toan NFC reader circuit can pass through the gap, as can an electricallyconductive path connecting to the inductive coil. In these and otherembodiments, a rotational alignment component comprising a magnet can bedisposed within the housing and outboard of (or outside a perimeter of)the annular magnetic alignment component.

In some embodiments, a wireless charging device can comprise: a housinghaving a charging surface; an inductive coil disposed within the housingand having an axis normal to the charging surface, the inductive coilbeing configured to transfer power wirelessly through the chargingsurface; an annular magnetic alignment component disposed within thehousing coaxial with and outboard of the inductive coil; and anear-field communication (NFC) coil disposed within the housing andcoaxial with the inductive coil, the NFC coil configured to wirelesslyexchange signals with another device through the charging surface. Inthese and other embodiments, the annular magnetic alignment componentcan include a plurality of sectors, each sector comprising: an innerarcuate region having a magnetic polarity oriented in a first axialdirection (e.g., having a south magnetic pole oriented toward thecharging surface); an outer arcuate region having a magnetic polarityoriented in a second axial direction opposite the first axial direction;and a non-magnetized central arcuate region disposed between the innerarcuate region and the outer arcuate region. In these and otherembodiments, an annular magnetic shield can be disposed at a distalsurface of the annular magnetic alignment component. In these and otherembodiments, the NFC coil is coupled to an NFC tag circuit, which can bea passive NFC tag circuit or an active NFC tag circuit. In these andother embodiments, the NFC coil is positioned between the inductive coiland the annular magnetic alignment component, e.g., in an annular gapbetween the inductive coil and the annular magnetic alignment component.In these and other embodiments, the first axial direction can be thesame direction for all of the sectors. Alternatively, alternatingsectors can have opposite first axial directions. In these and otherembodiments, each sector of the annular magnetic alignment componentincludes one or more arcuate magnets each having a quad-poleconfiguration. In these and other embodiments, the annular magneticalignment component can include a gap between two of the sectors. Anelectrically conductive path connected to the inductive coil can passthrough the gap, as can an electrically conductive path connecting theNFC coil to an NFC tag circuit.

In some embodiments, an accessory device can comprise: a housing havingan interface surface; an annular magnetic alignment component disposedwithin the housing and having an axis normal to the interface surface;and a near-field communication (NFC) coil disposed within the housingand coaxial with the annular magnetic alignment component, the NFC coilconfigured to wirelessly exchange signals with another device throughthe interface surface. In these and other embodiments, the annularmagnetic alignment component including a plurality of sectors, eachsector comprising: an inner arcuate region having a magnetic polarityoriented in a first axial direction; an outer arcuate region having amagnetic polarity oriented in a second axial direction opposite thefirst axial direction; and a non-magnetized central arcuate regiondisposed between the inner arcuate region and the outer arcuate region.In these and other embodiments, the NFC coil can be coupled to an NFCtag circuit. In these and other embodiments, the NFC coil can bepositioned inboard of the annular magnetic alignment component, andother components of an NFC tag circuit can be positioned inboard of theannular magnetic alignment component and/or in one or more gaps betweensectors of the annular magnetic alignment component. Alternatively, theNFC coil can be positioned outboard of the annular magnetic alignmentcomponent.

In some embodiments, a portable electronic device can comprise: ahousing having an interface surface; an inductive coil disposed withinthe housing and having an axis normal to the interface surface, theinductive coil being configured to transfer power wirelessly through theinterface surface; an annular magnetic alignment component disposedwithin the housing coaxial with and outboard of the inductive coil, theannular magnetic alignment component including a plurality of sectors,each sector having a magnetic orientation with a radial component; anear-field communication (NFC) coil disposed within the housing andcoaxial with the inductive coil, the NFC coil coupled to an NFC readercircuit and configured to wirelessly exchange signals with anotherdevice through the interface surface; a magnetometer disposed near theinterface surface and outboard of the annular magnetic alignmentcomponent; and control circuitry coupled to the magnetometer andconfigured to trigger operation of the NFC reader circuit based at leastin part on a change in a magnetic field detected by the magnetometer. Inthese and other embodiments, the magnetometer can be a three-axismagnetometer and the change in the magnetic field can includes a changein either or both of a magnitude or a direction of the magnetic field.In these and other embodiments, the control circuitry can be furtherconfigured to trigger operation of the NFC reader circuit in the eventthat the change in the magnetic field corresponds to an expected changeassociated with an accessory device having a second magnetic alignmentcomponent complementary to the annular magnetic alignment component ofthe portable electronic device becoming aligned with the portableelectronic device. In these and other embodiments, the NFC readercircuit can be operable in a plurality of operating modes associatedwith different types of accessory devices, and the control circuitry isfurther configured to select one of the operating modes for the NFCreader circuit based at least in part on the change in the magneticfield detected by the magnetometer. In these and other embodiments, thecontrol circuitry can be further configured to receive NFC tag data fromthe NFC reader circuit and to modify a behavior of the portableelectronic device based on the received NFC tag data. In these and otherembodiments, the NFC coil can be positioned in a gap between theinductive coil and the annular magnetic alignment component. In theseand other embodiments, the annular magnetic alignment component caninclude a plurality of sectors, each sector having a magneticorientation with a radial component, and the control circuitry can befurther configured to trigger operation of the NFC reader circuit in theevent that the change in the magnetic field corresponds to an expectedchange associated with an accessory device having a second magneticalignment component becoming aligned with the portable electronicdevice, wherein the second magnetic alignment component is a secondannular magnetic alignment component having a quad-pole magneticconfiguration that is complementary to the annular magnetic alignmentcomponent of the portable electronic device.

In some embodiments, a portable electronic device can comprise: ahousing having an interface surface; an annular magnetic alignmentcomponent disposed within the housing; a near-field communication (NFC)coil disposed within the housing and coaxial with the annular magneticalignment component, the NFC coil coupled to an NFC reader circuit andconfigured to wirelessly exchange signals with another device throughthe interface surface; a magnetometer disposed near the interfacesurface and outboard of the annular magnetic alignment component; andcontrol circuitry coupled to the magnetometer and configured to triggeroperation of the NFC reader circuit based at least in part on a changein a magnetic field detected by the magnetometer. In these and otherembodiments, the magnetometer can be a three-axis magnetometer and thechange in the magnetic field can include a change in either or both of amagnitude or a direction of the magnetic field. In these and otherembodiments, the control circuitry can be further configured to triggeroperation of the NFC reader circuit in the event that the change in themagnetic field corresponds to an expected change associated with anaccessory device having a second magnetic alignment componentcomplementary to the annular magnetic alignment component of theportable electronic device becoming aligned with the portable electronicdevice. In these and other embodiments, the NFC reader circuit can beoperable in a plurality of operating modes associated with differenttypes of accessory devices and wherein the control circuitry can befurther configured to select one of the operating modes for the NFCreader circuit based at least in part on the change in a magnetic fielddetected by the magnetometer. In these and other embodiments, thecontrol circuitry can be further configured to receive NFC tag data fromthe NFC reader circuit and to modify a behavior of the portableelectronic device based on the received NFC tag data. In these and otherembodiments, the annular magnetic alignment component includes aplurality of sectors, each sector having a magnetic orientation with aradial component. In these and other embodiments, the control circuitrycan be further configured to trigger operation of the NFC reader circuitin the event that the change in the magnetic field corresponds to anexpected change associated with an accessory device having a secondmagnetic alignment component becoming aligned with the portableelectronic device, wherein the second magnetic alignment component is asecond annular magnetic alignment component having a quad-pole magneticconfiguration that is complementary to the annular magnetic alignmentcomponent of the portable electronic device.

In some embodiments, a method of identifying an accessory can comprise:operating, by a portable electronic device having a first annularmagnetic alignment component, a magnetometer to monitor a magnetic fieldnear the first annular magnetic alignment component; detecting, by theportable electronic device, a change in the magnetic field indicativethat an accessory having a second annular magnetic alignment componentcomplementary to the first annular magnetic alignment component has comeinto proximity with the portable electronic device; and in response todetecting the change in the magnetic field, operating, by the portableelectronic device, an NFC reader circuit that includes an NFC coilcoaxial with the first annular magnetic alignment component to read anNFC tag of the accessory. In these and other embodiments, the change inthe magnetic field can include a change in either or both of a magnitudeor a direction of the magnetic field. In these and other embodiments,the NFC reader circuit is operable in a plurality of operating modesassociated with different types of accessory devices, and the method canfurther comprise selecting one of the operating modes for the NFC readercircuit based at least in part on the change in a magnetic fielddetected by the magnetometer. In these and other embodiments, the methodcan further comprise modifying a behavior of the portable electronicdevice based on identification data read from the NFC tag of theaccessory, such as changing an element displayed on a display of theportable electronic device.

In some embodiments, a wireless charging module can comprise: a housinghaving a charging surface and a second surface having an openingtherethrough (the opening can be opposite the charging surface orelsewhere on the housing); an inductive coil assembly disposed withinthe housing, the inductive coil assembly including an electricallyconductive coil; an annular magnetic alignment component disposed withinthe housing and surrounding the inductive coil assembly; and controlcircuitry disposed within the housing, the control circuitry beingcoupled to the electrically conductive coil and to a plurality ofexternal electrical contacts and being configured to operate theelectrically conductive coil to transfer power wirelessly through thecharging surface using input power received from the external electricalcontacts, where the external electrical contacts are exposed through theopening in the second surface of the housing. In these and otherembodiments, the annular magnetic alignment component can include aplurality of sectors, each sector comprising: an inner arcuate regionhaving a magnetic polarity oriented in a first axial direction; an outerarcuate region having a magnetic polarity oriented in a second axialdirection opposite the first axial direction; and a non-magnetizedcentral arcuate region disposed between the inner arcuate region and theouter arcuate region. In these and other embodiments, a conductivemidplate can be disposed within the housing. The midplate can have aproximal surface oriented toward the charging surface and a distalsurface opposite the proximal surface, and the inductive coil assemblycan be mounted on the proximal surface of the midplate. In these andother embodiments, the control circuitry can comprise a logic boardhaving circuit components mounted thereon. Where a midplate is present,the logic board can be mounted on the distal surface of the midplate.For instance, the midplate can have an opening therethrough, and thelogic board can be coupled to the electrically conductive coil throughthe opening in the midplate. In these and other embodiments, an annularmagnetic shield can be disposed at a distal surface of the annularmagnetic alignment component. In these and other embodiments, theexternal electrical contacts include a calibration contact, which can becovered with a sealant material following calibration. In these andother embodiments, the inductive coil assembly can further include: anelectric shield disposed between the electrically conductive coil andthe charging surface; and an electromagnetic shield covering a surfaceof the electrically conductive coil opposite the electric shield.

In some embodiments, a wireless charging module can comprise: a housinghaving a charging surface and a second surface having an openingtherethrough (the opening can be opposite the charging surface orelsewhere on the housing); an inductive coil assembly disposed withinthe housing, the inductive coil assembly including an electricallyconductive coil and an electromagnetic shield; an annular magneticalignment component disposed within the housing and surrounding theinductive coil assembly; a near-field communication (NFC) coil disposedwithin the housing and coaxial with the inductive coil assembly, the NFCcoil configured to wirelessly exchange signals with another devicethrough the charging surface; and control circuitry disposed within thehousing, the control circuitry being coupled to the electricallyconductive coil and to a plurality of external electrical contacts andbeing configured to operate the electrically conductive coil to transferpower wirelessly through the charging surface using input power receivedfrom the external electrical contacts, and the external electricalcontacts can be exposed through the opening in the second surface of thehousing. In these and other embodiments, the annular magnetic alignmentcomponent can include a plurality of sectors, each sector comprising: aninner arcuate region having a magnetic polarity oriented in a firstaxial direction; an outer arcuate region having a magnetic polarityoriented in a second axial direction opposite the first axial direction;and a non-magnetized central arcuate region disposed between the innerarcuate region and the outer arcuate region. In these and otherembodiments, the NFC coil can be coupled to an NFC tag circuit. In theseand other embodiments, the NFC coil can be positioned between theinductive coil assembly and the annular magnetic alignment component(e.g., in an annular gap between the inductive coil assembly and theannular magnetic alignment component). In these and other embodiments, aconductive midplate can be disposed within the housing, the midplatehaving a proximal surface oriented toward the charging surface and adistal surface opposite the proximal surface. The inductive coilassembly can be mounted on the proximal surface of the midplate with theelectromagnetic shield oriented toward the midplate. In these and otherembodiments, the control circuitry can comprise a logic board, and theNFC coil can be terminated into the logic board. Where a midplate ispresent, the logic board is mounted on the distal surface of themidplate. For instance, the midplate can have an opening therethrough,and the logic board can be coupled to the electrically conductive coilthrough the opening in the midplate.

In some embodiments, a wireless charging module can comprise: a housinghaving a charging surface and a second surface having an openingtherethrough; an inductive coil assembly disposed within the housing,the inductive coil assembly including an electrically conductive coiland an electromagnetic shield; an annular magnetic alignment componentdisposed within the housing and surrounding the inductive coil assembly;a rotational alignment component comprising a magnet disposed within thehousing outside a perimeter of the annular magnetic alignment component;and control circuitry disposed within the housing, the control circuitrybeing coupled to the electrically conductive coil and to a plurality ofexternal electrical contacts and being configured to operate theelectrically conductive coil to transfer power wirelessly through thecharging surface using input power received from the external electricalcontacts, where the external electrical contacts are exposed through theopening in the second surface of the housing. In these and otherembodiments, the annular magnetic alignment component can include aplurality of sectors, each sector comprising: an inner arcuate regionhaving a magnetic polarity oriented in a first axial direction; an outerarcuate region having a magnetic polarity oriented in a second axialdirection opposite the first axial direction; and a non-magnetizedcentral arcuate region disposed between the inner arcuate region and theouter arcuate region. In these and other embodiments, a conductivemidplate can be disposed within the housing, the midplate having aproximal surface oriented toward the charging surface and a distalsurface opposite the proximal surface. The inductive coil assembly canbe mounted on the proximal surface of the midplate with theelectromagnetic shield oriented toward the midplate. In these and otherembodiments, the control circuitry can comprise a logic board. Where amidplate is present, the logic board can be mounted on the distalsurface of the midplate. For instance, the midplate can have an openingtherethrough, and the logic board can be coupled to the electricallyconductive coil through the opening in the midplate. In these and otherembodiments, the rotational alignment component can comprise a magnethaving at least two different regions of opposing magnetic orientations.

In some embodiments, an alignment module can include: an annularmagnetic alignment component including a plurality of arcuate magnets;and an encapsulating structure surrounding and holding the arcuatemagnets in an annular arrangement. Each arcuate magnet can have, forexample: an inner arcuate region having a magnetic polarity oriented ina first axial direction; an outer arcuate region having a magneticpolarity oriented in a second axial direction opposite the first axialdirection; and a non-magnetized central arcuate region disposed betweenthe inner arcuate region and the outer arcuate region. In these andother embodiments, the encapsulating structure can have an annularshape. For instance, the encapsulating structure can comprise an annularfront enclosure and an annular rear enclosure joined at inner and outeredges thereof. The annular front enclosure and the annular rearenclosure can made of plastic or other materials. Joining of the annularfront enclosure and the annular rear enclosure can be by a weld, or theannular front enclosure can be formed in a first injection molding stageafter which the annular rear enclosure is injection molded onto theannular front enclosure (or vice versa). In these and other embodiments,the encapsulating structure can comprise an annular front enclosure, anannular back enclosure, an annular inner side enclosure and an annularouter side enclosure and wherein the annular front enclosure and theannular back enclosure are joined to the annular inner side enclosureand the annular outer side enclosure by adhesive. In these and otherembodiments, an alignment module can also comprise: a rotationalalignment component comprising a rectangular magnet, and theencapsulating structure can hold the rectangular magnet in a fixedposition outboard of the annular magnetic alignment component.

In some embodiments, an alignment module can comprise: an annularmagnetic alignment component including a plurality of arcuate magnets; arotational alignment component comprising a rectangular magnet anddisposed outside a perimeter of the annular magnetic alignmentcomponent; and an encapsulating structure holding the annular magneticalignment component and the rotational alignment component in a fixedspatial relationship to each other. Each arcuate magnet can have: aninner arcuate region having a magnetic polarity oriented in a firstaxial direction; an outer arcuate region having a magnetic polarityoriented in a second axial direction opposite the first axial direction;and a non-magnetized central arcuate region disposed between the innerarcuate region and the outer arcuate region. In these and otherembodiments, the encapsulating structure can comprise: a front planarlayer; a back planar layer; and a magnet-holding layer, themagnet-holding layer having a circular opening therethrough toaccommodate the annular magnetic alignment component and a rectangularopening therethrough to accommodate the rectangular magnet. In these andother embodiments, the magnet-holding layer, the arcuate magnets, andthe rectangular magnet can have equal thicknesses, and themagnet-holding layer includes a disc of material filling a regioninboard of the annular magnetic alignment component. In these and otherembodiments, a first adhesive layer can attach the front planar layer tothe magnet-holding layer, and a second adhesive layer can attach theback planar layer to the magnet-holding layer. In these and otherembodiments, the front planar layer and the back planar layer can berectangular layers with rounded corners. In these and other embodiments,the encapsulating structure can have an opening through a region insidean inner perimeter of the annular magnetic alignment component.

In some embodiments, an alignment module can comprise: an annularmagnetic alignment component including a plurality of arcuate magnets,an encapsulating structure surrounding and holding the arcuate magnetsin an annular arrangement; and a near-field communication (NFC) coildisposed within the encapsulating structure and coaxial with the annularmagnetic alignment component, the NFC coil coupled to an NFC tagcircuit. In these and other embodiments, each arcuate magnet can have:an inner arcuate region having a magnetic polarity oriented in a firstaxial direction; an outer arcuate region having a magnetic polarityoriented in a second axial direction opposite the first axial direction;and a non-magnetized central arcuate region disposed between the innerarcuate region and the outer arcuate region. In these and otherembodiments, the NFC coil can be disposed inboard of the annularmagnetic alignment component, and other NFC tag circuit components canbe disposed inboard of the annular magnetic alignment component and orin gaps between certain arcuate magnets of the annular magneticalignment component. In these and other embodiments, the encapsulatingstructure can comprise: a front planar layer; a back planar layer; and amagnet-holding layer, the magnet-holding layer having a circular openingtherethrough to accommodate the annular magnetic alignment component(and the NFC coil). In these and other embodiments, the magnet-holdinglayer and the arcuate magnets can have equal thicknesses. In these andother embodiments, the magnet-holding layer can include a disc ofmaterial filling a region interior to the annular magnetic alignmentcomponent and the NFC coil. In these and other embodiments, an alignmentmodule can further comprise: a rotational alignment component comprisinga rectangular magnet and disposed outboard (or outside a perimeter) ofthe annular magnetic alignment component, and the magnet-holding layercan have a rectangular opening therethrough to accommodate therotational alignment component.

Accordingly, although the invention has been described with respect tospecific embodiments, it will be appreciated that the invention isintended to cover all modifications and equivalents within the scope ofthe following claims.

What is claimed is:
 1. A portable electronic device comprising: ahousing having an interface surface; an inductive coil disposed withinthe housing and having an axis normal to the interface surface, theinductive coil being configured to transfer power wirelessly through theinterface surface; an annular magnetic alignment component disposedwithin the housing coaxial with and outboard of the inductive coil, theannular magnetic alignment component including a plurality of sectors,each sector having a magnetic orientation with a radial component; anear-field communication (NFC) coil disposed within the housing andcoaxial with the inductive coil, the NFC coil coupled to an NFC readercircuit and configured to wirelessly exchange signals with anotherdevice through the interface surface; a magnetometer disposed near theinterface surface and outboard of the annular magnetic alignmentcomponent; and control circuitry coupled to the magnetometer andconfigured to trigger operation of the NFC reader circuit based at leastin part on a change in a magnetic field detected by the magnetometer. 2.The portable electronic device of claim 1 wherein the magnetometer is athree-axis magnetometer and the change in the magnetic field includes achange in either or both of a magnitude or a direction of the magneticfield.
 3. The portable electronic device of claim 1 wherein the controlcircuitry is further configured to trigger operation of the NFC readercircuit in the event that the change in the magnetic field correspondsto an expected change associated with an accessory device having asecond magnetic alignment component complementary to the annularmagnetic alignment component of the portable electronic device becomingaligned with the portable electronic device.
 4. The portable electronicdevice of claim 3 wherein the NFC reader circuit is operable in aplurality of operating modes associated with different types ofaccessory devices and wherein the control circuitry is furtherconfigured to select one of the operating modes for the NFC readercircuit based at least in part on the change in the magnetic fielddetected by the magnetometer.
 5. The portable electronic device of claim1 wherein the control circuitry is further configured to receive NFC tagdata from the NFC reader circuit and to modify a behavior of theportable electronic device based on the received NFC tag data.
 6. Theportable electronic device of claim 1 wherein the NFC coil is positionedin a gap between the inductive coil and the annular magnetic alignmentcomponent.
 7. The portable electronic device of claim 1 wherein theannular magnetic alignment component includes a plurality of sectors,each sector having a magnetic orientation with a radial component. 8.The portable electronic device of claim 7 wherein the control circuitryis further configured to trigger operation of the NFC reader circuit inthe event that the change in the magnetic field corresponds to anexpected change associated with an accessory device having a secondmagnetic alignment component becoming aligned with the portableelectronic device, wherein the second magnetic alignment component is asecond annular magnetic alignment component having a quad-pole magneticconfiguration that is complementary to the annular magnetic alignmentcomponent of the portable electronic device.
 9. A portable electronicdevice comprising: a housing having an interface surface; an annularmagnetic alignment component disposed within the housing; a near-fieldcommunication (NFC) coil disposed within the housing and coaxial withthe annular magnetic alignment component, the NFC coil coupled to an NFCreader circuit and configured to wirelessly exchange signals withanother device through the interface surface; a magnetometer disposednear the interface surface and outboard of the annular magneticalignment component; and control circuitry coupled to the magnetometerand configured to trigger operation of the NFC reader circuit based atleast in part on a change in a magnetic field detected by themagnetometer.
 10. The portable electronic device of claim 9 wherein themagnetometer is a three-axis magnetometer and the change in the magneticfield includes a change in either or both of a magnitude or a directionof the magnetic field.
 11. The portable electronic device of claim 9wherein the control circuitry is further configured to trigger operationof the NFC reader circuit in the event that the change in the magneticfield corresponds to an expected change associated with an accessorydevice having a second magnetic alignment component complementary to theannular magnetic alignment component of the portable electronic devicebecoming aligned with the portable electronic device.
 12. The portableelectronic device of claim 11 wherein the NFC reader circuit is operablein a plurality of operating modes associated with different types ofaccessory devices and wherein the control circuitry is furtherconfigured to select one of the operating modes for the NFC readercircuit based at least in part on the change in a magnetic fielddetected by the magnetometer.
 13. The portable electronic device ofclaim 9 wherein the control circuitry is further configured to receiveNFC tag data from the NFC reader circuit and to modify a behavior of theportable electronic device based on the received NFC tag data.
 14. Theportable electronic device of claim 9 wherein the annular magneticalignment component includes a plurality of sectors, each sector havinga magnetic orientation with a radial component.
 15. The portableelectronic device of claim 9 wherein the control circuitry is furtherconfigured to trigger operation of the NFC reader circuit in the eventthat the change in the magnetic field corresponds to an expected changeassociated with an accessory device having a second magnetic alignmentcomponent becoming aligned with the portable electronic device, whereinthe second magnetic alignment component is a second annular magneticalignment component having a quad-pole magnetic configuration that iscomplementary to the annular magnetic alignment component of theportable electronic device.
 16. A method of identifying an accessory,the method comprising: operating, by a portable electronic device havinga first annular magnetic alignment component, a magnetometer to monitora magnetic field near the first annular magnetic alignment component;detecting, by the portable electronic device, a change in the magneticfield indicative that an accessory having a second annular magneticalignment component complementary to the first annular magneticalignment component has come into proximity with the portable electronicdevice; and in response to detecting the change in the magnetic field,operating, by the portable electronic device, an NFC reader circuit thatincludes an NFC coil coaxial with the first annular magnetic alignmentcomponent to read an NFC tag of the accessory.
 17. The method of claim16 wherein the change in the magnetic field includes a change in eitheror both of a magnitude or a direction of the magnetic field.
 18. Themethod of claim 16 wherein the NFC reader circuit is operable in aplurality of operating modes associated with different types ofaccessory devices and wherein the method further comprises selecting oneof the operating modes for the NFC reader circuit based at least in parton the change in a magnetic field detected by the magnetometer.
 19. Themethod of claim 16 further comprising: modifying a behavior of theportable electronic device based on identification data read from theNFC tag of the accessory.
 20. The method of claim 19 wherein modifying abehavior of the portable electronic device includes changing an elementdisplayed on a display of the portable electronic device.